cssi/SciSciGPT-SciSciNet huggingface dataset:
Design and synthesis of amphipathic antimicrobial peptides.

A large proportion of antimicrobial peptides share a common structural feature that is critical to their antimicrobial activity, i.e. amphipathic alpha-helices. The amphipathy of a polypeptide chain can be quantitated through the value of the hydrophobic moment. Generally, antimicrobial peptides are characterized by high hydrophobic moment and low hydrophobicity values. Using these criteria we have identified two short segments that possess hydrophobic moment properties associated with known antimicrobial peptides. Using in vitro assays the segment derived from the protein perforin displays no antifungal or antibacterial activity and, while showing no alpha-helicity in buffer or liposomes, exhibits a modest degree of alpha-helical structure in the presence of the alpha-helical inducer, 2,2,2-trifluoroethanol. However, rational modifications result in a derivative which assumes an alpha-helical conformation in the presence of liposomes, exhibits potent antifungal activity against plant fungal pathogens, has significant antibacterial activity, effects leakage of a fluorescent dye from acidic liposomes and is devoid of hemolytic activity. Results are also presented for a segment derived from the human immunodeficiency virus envelope protein. We suggest that the identification of putative amphipathic structures in proteins may provide a useful starting strategy in the design and synthesis of antimicrobial peptides.
Case study: Using Smart Cards with PKI to implement data access control for health information systems

Data access control is an important topic in Information Assurance (IA) curriculum. This paper presents a case study of the data access control for health information system. This case study is developed to enhance IA education by providing conceptual information that is relevant and parallel the materials that are learned in the classroom. The case study objective, materials and discussion questions are developed. Students will be able read the case study materials and answer questions based on their reading. The learning goal of this case study is to help students understand the need for data access control, the technologies that are proposed, and how they protect the data's confidentiality, integrity, authentication and non-repudiation. This case study materials can be used in Network Security, Web Security, Data Access Control related undergraduate courses.
Effects of the minor groove pyrimidine nucleobase functional groups on the stability of duplex DNA: the impact of uncompensated minor groove amino groups.

DNA sequences containing four types of analog nucleosides are described. All four are pyridine derivatives constructed as C-nucleosides so that they mimic the pyrimidine derivatives 2′-deoxyuridine, thymidine or 2′-deoxycytidine, but in all cases the analogs lack the corresponding O2-carbonyls that in duplex DNA are located in the minor groove. In place of the O2-carbonyl is a hydrogen atom, a polar fluorine atom, or a nonpolar methyl group. The described C-nucleosides have native-like bidentate Watson–Crick hydrogen-bonding faces and can form essentially normal W-C base pairs of varying stability with A or G. In each modified base pair, two inter-residue hydrogen bonds should be present. In spite of a common number of interstrand hydrogen bonds, the thermodynamic stabilities of the prepared duplexes, each containing two analog base pairs, vary dramatically. Most notably, base pairs containing uncompensated purine amino groups (those lacking a hydrogen-bonding partner) in the minor groove exhibit the most dramatic reductions in thermodynamic stability. Removal of such uncompensated amino groups results in increased duplex stability. Base pairs containing fluorine in the minor groove positioned adjacent to an amino group seem to enhance duplex stability marginally (relative to H or CH3), but there is little evidence to suggest that fluorine is an effective hydrogen-bonding partner in these systems. The presence of minor groove methyl groups results in the least stable duplexes in each series of sequences. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 183–195, 2007. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Sleep Study Abnormalities in Children With Attention Deficit Hyperactivity Disorder

The study objective was to describe polysomnographic findings in children with attention deficit hyperactivity disorder (ADHD) with diverse sleep problems. Polysomnographic data were retrospectively analyzed for 33 children (age 3-16 years) with ADHD who had sleep studies performed for diverse sleep complaints. Eight patients (24%) had obstructive sleep apnea, 10 (30%) had periodic limb movements of sleep, 8 (24%) had upper airway resistance syndrome, and 5 (15%) had obstructive hypoventilation. The ADHD group showed decreased sleep efficiency, increased arousal index, increased wake after sleep onset, decreased oxygen saturation nadir, and increased snoring, compared with control subjects. Compared with ADHD children without sleep disordered breathing, those who had sleep disordered breathing were significantly more obese and had more sleep architectural abnormalities (including increased sleep latency, increased rapid eye movement latency, increased wake after sleep onset, and increased arousal index with more oxygen desaturations), although total sleep time and sleep efficiency were not significantly different. Sleep disordered breathing and periodic limb movements of sleep appear to be common among children with ADHD who have symptoms of disturbed sleep.
A Note on Optimal Matching With Variable Controls Using the Assignment Algorithm

The assignment algorithm is an old, well-known, widely implemented, fast, combinatorial algorithm for optimal matching in a bipartite graph. This note proposes a method for using the assignment algorithm to solve the problem of optimal matching with a variable number of controls, in which there is a choice not only of who to select as a control for each treated subject, but also of how many controls to have for each treated subject. The strategy uses multiple copies of treated subjects and sinks with zero cost to absorb extra controls. Also, it is shown that an optimal matching with variable numbers of controls cannot be obtained by starting with an optimal pair matching and adding the closest additional controls. An example involving mortality after surgery in Pennsylvania hospitals is used to illustrate the method.
A comparison between a fixed and a variable fishing mortality control rule used to manage the cod stock off southern Labrador and the east coast of Newfoundland

Scientific advice for the management of the cod stock off southern Labrador and eastern Newfoundland (northern cod) was provided based on a fixed fishing mortality rate approach from 1972 to 1988. In 1989, with declining stock size and a requirement from the fishing industry for greater quota stability, variable fishing mortality rate approaches were introduced. Departure from fixed fishing mortality approaches allowed the fishing mortality to escalate, turning what might have been a severe stock decline under a fixed fishing mortality rate into a collapse. Given the time series of recruitment estimated for the stock, the trajectory of simulated stock biomass under different fixed levels of fishing mortality is compared with what is estimated to have transpired. Two control rules which were used in providing the scientific advice for the stock, one based on fixed fishing mortality rate and one based on variable mortality rate, are explored through the use of a population model which includes random error in the estimates of abundance. The effect of systematic under-estimation of fishing mortality at the time of the assessment (the retrospective problem) is also investigated. The control rule based on a variable fishing mortality approach is shown to have a greater propensity for causing severe spawner biomass declines under the modelled conditions.
The inhibitory effect of cortisone on the synthesis of mouse liver DNA.

Abstract The use of microspectrophotometry, autoradiography and polyploid frequency determinations demonstrated that cortisone, when administered to five week old mice, inhibits the synthesis of liver DNA. The data presented suggest that this effect is transient. Evidence is cited which supports the possibility that this effect is nonspecific and perhaps characteristic of steroid hormones.
Copper cables: Should they be phased out as last mile broadband solutions?

The fundamental building block of last mile broadband connections for the telecommunications industry is the copper cabling systems that have traditionally underpinned the networks. Time has seen tremendous change in this core component of the network, with result being silica-based fiber optics are championed as the de facto replacement technology for traditional copper cabling in the last mile. This paper will provide a survey and discussion of the current status of copper cabling in networks. It will examine the strengths of copper verses fiber optics. It will explore the effectiveness of recent technological advances made in delivering broadband over copper. It will also review the current economic models relating to cable deployments. Finally, an analysis will be presented that attempts to answers the question of phasing out copper.
Beneficial effects of angiotensin-converting enzyme inhibitors during acute revascularization

Abstract Background . This experimental study was undertaken to determine whether using angiotensin-converting enzyme inhibitors during surgical revascularization of acutely ischemic myocardium would improve wall motion and limit infarct size. Methods . Twenty pigs underwent 90 minutes of occlusion of the second and third diagonal arteries followed by 45 minutes of cardioplegic arrest and 180 minutes of reperfusion. In 10 animals, the angiotensin-converting enzyme inhibitor enalaprilat (0.05 mg/kg) was infused intravenously during coronary occlusion; 10 other animals received no angiotensin-converting enzyme inhibitors. Ischemic damage was assessed by the number of cardioversions required for ventricular tachycardia or fibrillation; wall motion scores using echocardiography (4 = normal to −1 = dyskinesia); and infarct size using histochemical staining. Epicardial coronary artery vasomotor function was assessed using standard organ chamber methodology. Results . Enalaprilat-treated hearts had the least amount of ventricular irritability (0.84 ± 0.24 versus 2.77 ± 0.22 cardioversions; p p p Conclusions . Angiotensin-converting enzyme inhibitors reduce myocardial damage during surgical revascularization of acutely ischemic myocardium.
Maximizing efficiency in the transition to a coal-based economy

Abstract Energy is the lynchpin of modern society. Since the early 1970s, growing dependence on foreign energy sources, oil in particular, has constrained US independence in foreign policy, and at times, inhibited economic stability and growth. Addressing oil dependence is politically and economically complex. Proposed solutions are multifaceted with various objectives such as energy efficiency and resource substitution. One solution is the partial transition from an oil- to coal-based economy. A number of facts support this solution including vast coal reserves in the US and the relative price stability of coal. However, several roadblocks exist. These include uncertain recoverable reserves and the immaturity of “clean” coal technologies. This paper provides a first order analysis of the most efficient use of coal assuming the transition from oil to coal is desirable. Scenario analysis indicates two possible transition pathways: (1) bring the transportation sector onto the electric grid and (2) use coal-to-liquid fuels to directly power vehicles. The feasibility of each pathway is examined based on economic and environmental factors, among which are energy availability, affordability and efficiency, and environmental sustainability. Results indicate that partial transition of the transportation sector onto the electric grid offers the more viable solution for coal-based reduction of the US oil dependence.
Quantitative Trait Loci Analysis of Structural and Material Skeletal Phenotypes in C57BL/6J and DBA/2 Second-Generation and Recombinant Inbred Mice†

QTL analyses identified several chromosomal regions influencing skeletal phenotypes of the femur and tibia in BXD F2 and BXD RI populations of mice. QTLs for skeletal traits co-located with each other and with correlated traits such as body weight and length, adipose mass, and serum alkaline phosphatase. Introduction Past research has shown substantial genetic influence on bone quality, and the impact of reduced bone mass on our aging population has heightened the interest in skeletal genetic research.
Direct-gap Ge/GeSn/Si and GeSn/Ge/Si heterostructures

Abstract A theoretical proposal is given for creating direct-gap semiconductor layers in silicon-based Group IV heterostructures. Based upon recent bandstructure calculations for pseudomorphic Ge/GeSi and GeSi/Ge, we predict a strain-induced Γc-Lc direct-gap crossover (λg ∼ 2.2 μm) in tensile Ge/Ge0.87Sn0.13 and in compressive Ge0.98Sn0.02/Ge. We used linear extrapolation of band-edge curves. The direct-gap structures are potentially useful in laser diodes, electrooptic modulators, and photodetectors.
Transfusion-Induced Immunomodulation and Its Clinical Consequences

The bulk of experimental and clinical data support the theory that homologous transfusion causes significant down-regulation of immunologic functions in a number of settings. These changes in immune function may account for the beneficial associations of transfusion with increased renal allograft survival, and decreased recurrence in Crohn's disease. Conversely, these transfusion-induced effects may be responsible in part for the deleterious association of homologous transfusion with increased cancer recurrence, and increased posttransfusion bacterial and viral infection rates. Host defenses against malignancy and infection may in some instances be severely compromised by transfusions of homologous blood, but the circumstances under which this occurs need to be better defined. Likewise, the hypothesis that modification of blood components to contain fewer leukocytes or less plasma might ameliorate these effects is attractive, but little or no data exist to support or refute it. Future clinical studies will no doubt address these issues.
ACE - A Model Centered REU Program Standing on the Three Legs of CSE: Analysis, Computation and Experiment

Abstract Enhancing REU (research experience for undergraduates) has become a popular strategy for many selective universities to enhance quality of undergraduate education and recruit gifted new students. The university that the authors are affiliated has set REU as one of the major outcomes for our QEP (quality enhancement program) for next 5 years. This paper presents a model centered REU program entitled as ACE standing for Analysis, Computation and Experiment. As a work in progress, the program is planned to run for the next 5 years and to serve for 20-30 undergraduate students who are gifted in mathematics and computing annually. ACE is to use interdisciplinary research projects, the guided exploration based on sound pedagogical practice and the top niche analogical and virtual dual lab facility bring measurable impacts to over a hundred of gifted undergraduates.
A coupled-cluster approach to the relative strains in [1.1.1]propellane, its derivatives and hetero[1.1.1]propellanes

The molecule [1.1.1]propellane and its neutral boron, nitrogen, oxygen, sulphur, S–O, and SO2 analogs as well as the methyl, hexafluoro, and tri-carbonyl substituted derivatives have been investigated by theoretical calculations at the coupled-cluster singles and doubles level with an augmented polarized double zeta basis set. The geometries were optimized and vibrational analysis was carried out for each species. The main objective of this study was to determine the relative strain in these systems, which in turn is a predictor of stability and reactivity providing valuable information about potentially viable synthetic targets. The systems with the least strain are the nitrogen, boron and the S–O analogs, whereas the SO2 substituted molecule and the hexafluoride and tricarbonyl substituted analogs exhibited the largest amount of strain. Geometrical features are also investigated and it is demonstrated that non-bonded repulsive interactions contribute significantly to the strain in some of the systems si...
The denaturation of orosomucoid

Abstract Highly purified human orosomucoid exhibits apparent multistate behavior on thermal denaturation, with Δ H (cal) for the transition being 119 kcal/mol at pH 7.4. Asialoorosomucoid denatured similarly. A domain structure could not be demonstrated for orosomucoid with cyanogen bromide fragments, although some reannealing of these did occur. It is suggested that the source of the apparent multistate behavior may lie in the existence of polypeptide variants, known to be present in orosomucoid. Although some polymerization occurs on heating, the unpolymerized material shows reversible thermal denaturation behavior. The presence of low concentrations of ethanol induces a significant endotherm which moves to lower temperatures with increasing ethanol concentration. This endotherm was irreversible in the continued presence of ethanol.
Characterization of TEMPO-oxidized Cellulose Nanofibers in Aqueous Suspension by Small-Angle X-Ray Scattering

Cellulose nanofibers, extracted from wood pulps using the (2,2,6,6-tetramethylpiperidine-1-yl)oxyl (TEMPO)-mediated oxidation method, are low-cost, sustainable and high-performance materials with potential usage in many applications. The structural information of these cellulose nanofibers in aqueous suspension was characterized by synchrotron small-angle X-ray scattering (SAXS). A simplified ribbon model having a near rectangular cross section was found to give the best fit to the SAXS results. The analytical expression of the ribbon model also led to a higher calculation efficiency compared with the more conventional parallelepiped model. The extracted structural information included the cross-section size and size distribution of the cellulose nanofibers. For example, for nanofibers prepared from the dried pulp of the maritime pine, the size-weighted averages of thickness and width were 3.2 and 12.7 nm, respectively, and the corresponding standard deviations were 2.2 and 5.5 nm, respectively. The scattering results of the size-weighted average of the nanofiber width are also consistent with those determined directly from transmission electron microscopy.
Direct-to-Earth communications with Mars Science Laboratory during Entry, Descent, and Landing

Mars Science Laboratory (MSL) undergoes extreme heating and acceleration during Entry, Descent, and Landing (EDL) on Mars. Unknown dynamics lead to large Doppler shifts, making communication challenging. During EDL, a special form of Multiple Frequency Shift Keying (MFSK) communication is used for Direct-To-Earth (DTE) communication. The X-band signal is received by the Deep Space Network (DSN) at the Canberra Deep Space Communication complex, then down-converted, digitized, and recorded by open-loop Radio Science Receivers (RSR), and decoded in real-time by the EDL Data Analysis (EDA) System. The EDA uses lock states with configurable Fast Fourier Transforms to acquire and track the signal. RSR configuration and channel allocation is shown. Testing prior to EDL is discussed including software simulations, test bed runs with MSL flight hardware, and the in-flight end-to-end test. EDA configuration parameters and signal dynamics during pre-entry, entry, and parachute deployment are analyzed. RSR and EDA performance during MSL EDL is evaluated, including performance using a single 70-meter DSN antenna and an array of two 34-meter DSN antennas as a back up to the 70-meter antenna.
Sustained attention in combat-related posttraumatic stress disorder

There is substantial evidence that PTSD patients have information processing abnormalities for stimuli that are highly relevant to the traumas they have endured. The goal of the present study was to examine whether this extends to neutral stimuli as well. Twenty-four male Vietnam combat veterans with PTSD were compared to fifteen normal male comparison subjects on their performance on a sensitive measure of sustained attention, the Continuous Performance Test-Identical Pairs version (CPT-IP). PTSD subjects did not differ from controls in their ability to discriminate target stimuli from background noise on the CPT. Additionally they performed as well as controls, even in the presence of external distraction. Thus, this study did not find a generalized deficit in attention associated with PTSD on the CPT-IP. Nevertheless, further clarification of the nature of the information processing disturbance in PTSD is warranted.
Cross-linkers control the viscoelastic properties of soybean oil-based biomaterials

Because of environmental concerns, biodegradable materials have been of increasing research interest over the last several years. Previously, we reported on a biobased material developed from epoxidized soybean oil (ESO) that displayed viscoelastic behavior similar to synthetic rubbers or plastics. In this work, the viscoelastic properties of several biomaterials made from ESO cross-linked by different amounts of two different cross-linking agents were investigated. The composites exhibited different glass transition temperatures and viscoelastic behaviors depending on the type and amount of cross-linker used. Higher glass transition temperatures and stronger viscoelastic properties of the materials were found with a greater amount of cross-linker. Comparing agent triethylene glycol diamine (TGD) with agent triethylenetriamine (TETA), we found that the material cross-linked by TETA had a higher glass transition temperature and stronger viscoelastic solid properties than the material cross-linked by the agent TGD.
Exploring Mirrors, Recreating Science and History, Becoming a Class Community.

A teacher narrates from activities and discussions that arose among undergraduates and herself while doing critical explorations of mirrors. Surprised by light's behaviors, the students responded with curiosity, losing their dependence on answers as the format of school knowledge. Inadequacies in how participants supposed light works emerged in the context of reinventing historical discoveries, including Ptolemy's second century AD account of how curved mirrors reflect, Chinese burning mirrors reported in the Han dynasty (206 BC–220 AD), and a ninth century AD Arabic translation of Euclid's surveying proposition. Using historical accounts only as a starting point and motivation, students' improvisational experiments explored personal interests and provided grounds for synthesizing new understandings of light and learning, and for forming relationships of community among each.
The Postmodernization of Death and Dying

The very concept of postmodernity suggests a significant change in the conduct of contemporary social life. Five aspects of this change are described. They are: the normalization of persistent and diffuse change; the abandonment of the concept of nature as necessarily embodying lawful regularity; the death of telos, or the discrediting of the concept of a history as a master, purposeful narrative; adaptations to largely unanticipated levels of individuation; and potential changes in the politics of the self. Implications of these changes are explored by speculative consideration of their impacts on death and dying.
Role of “Adherence Oxides” in the Development of Chemical Bonding at Glass-Metal Interfaces

Chemical bonding, a requirement for adherence, is developed at glass-metal interfaces by achieving and maintaining equilibrium compositions at the interfaces. Reactions between iron and glasses with and without “adherence oxides” were studied by thermogravimetry, optical microscopy, and electron probe microanalysis. Adherence oxides result in the formation of alloys at the interface that tend to maintain equilibrium with the adjoining glass over an extended time and enhance atmospheric oxidation of the metal. The occurrence of dendrites in the bulk glass and the function of a “nickel flash” in porcelain enameling are discussed in terms of these reactions.
Identification of Methyl Octanoate Derivatives from Autoxidized Methyl Linoleate by Mass Spectrometry, Nuclear Magnetic Resonance and Infra-red Spectroscopy

FROM our investigations on the volatiles from the mild autoxidation of methyl linoleate, we have already reported the isolation and identification of methyl octanoate1. Frankel et al.2 postulated a mechanism for the decomposition of unsaturated hydroperoxy esters that predicts the formation not only of methyl octanoate but also of 8-formyl methyl octanoate, and 8-hydroxy methyl octanoate from 9-hydroperoxy methyl linoleate. Ellis3 also postulated the formation of semi-aldehydes from oxidation of unsaturated fatty acids. This communication reports further results on an extract of the autoxidized oil which show the presence of 8-formyl methyl octanoate and the formate of 8-hydroxy methyl octanoate (8-formoxy methyl octanoate).
EVOLUTION OF THE GASEOUS CONTENT OF THE UNIVERSE

Results of a new spectroscopic survey for damped Ly-alpha absorption systems conducted at ultraviolet wavelengths are combined with those of previous surveys conducted at optical wavelengths in order to examine the evolution of the gaseous content of the universe at z between 0 and 3.5. Implications for scenarios of galaxy formation and evolution are discussed.
Characterizing Limit Cycles in the Cassini Thrust Vector Control System

The Cassini spacecraft dynamics telemetry during long main engine burns has indicated the presence of stable limit cycles between 0.03 and 0.05 Hz frequencies. Even though these limit cycles have been observed in telemetry, they have not hindered the spacecraft performance to any degree of concern. The performance of the main engine thrust vector control system has been excellent throughout the prime and extended missions. However, it is important to understand these stable limit cycles from a controller design viewpoint. It is proposed that the observed limit cycles in the dynamics telemetry appear from a stable interaction between the unmodeled nonlinear elements and the linear main engine thrust vector control system. This paper focuses on one such nonlinearity that emerges from the gear backlash in the engine gimbal actuator system. The gear backlash nonlinearity is modeled via a describing function, and the interaction between the nonlinear element model and the overall dynamics of the spacecraft is ...
Improved separations procedures for isolating 2,3,7,8-TCDD and 2,3,7,8-TCDF from chemically-complex aqueous and solid sample martrices and for definitive quantitation of these isomers at ppq to ppt concentrations

Abstract An analytical procedure has been developed and validated for quantitatively measuring 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) present at parts-per-trillion (ppt) to parts-per-quadrillion (ppq) concentrations in various paper manufacturing process and waste water samples.
Measurement of Kinetic Zone Temperature and Heat Transfer Coefficient in the Lost Foam Casting Process

A thermometric technique has been developed to study the thermal characteristics of the foam-metal interaction in the lost foam casting process. A cylindrical foam pattern and heated steel block have been used to estimate the endothermic losses associated with the thermal degradation of the expanded polystyrene at the metal front. Thermocouple readings have been analyzed to determine the temperature of the kinetic zone between the advancing metal front and the receding foam pattern. The heat transfer coefficient between the metal front and the foam pattern has been calculated from the thermal data at the simulated metal front. The results confirmed that the endothermic degradation of the polystyrene pattern at the metal front introduced a steep thermal gradient in the metal and a consistently increasing heat flux. It is found that the heat transfer coefficient, initially 150 W/m2 ·K increases to 220 ~ 300 W/m2 ·K during the process. Foam density has marginal effect on the heat flux and heat transfer coefficient, whereas the increase of simulated metal front velocity enhances the heat transfer at the metal front. The kinetic zone temperature is measured to be in the range of 150 to 290°C with an average of 200°C and a gaseous gap size of 1 to 4 cm.Copyright © 2004 by ASME
Hormonally Influenced Hemangioma

The growth of vascular tumors in response to hormonal stimulation is a well-documented and generally accepted fact. The development of nevus-araneous-like hemangiomata associated with the high hormonal blood levels of pregnancy has been described by Walsh and Becker, Forman, Zeisler, Feldman, and others. The "pregnancy tumor," frequently mentioned in the dental literature and described by Thoma and Miller as a fibroangioma or a form of epulis, is another example of the growth of vascular elements in response to rising hormonal titers. Neither the telangiectasis nor "pregnancy tumors" are true neoplasmas, but they do represent cyclic hyperplasia of vascular tissues. The effect of endocrine stimulation on cavernous hemangiomas, true neoplasmas, in contradistinction to the aforementioned hyperplasias, remains a controversial issue. Although Kitlowski has described flare-ups of these tumors at the time of puberty and of menopause and during pregnancy, Johnson, Ghormley, and Dockerty in a recent review of hemangiomas of the
The regeneration niche of desert ants: effects of established colonies

We marked the sites chosen by 338 foundress queens of two desert ant species (Veromessor pergandei and Myrmecocystus flaviceps) and monitored changes in the spacing of both species and the foraging activity at V. pergandei young nests. Although the long established colonies of both species tend intraspecifically toward regular dispersion, queens of both species were intraspecifically clumped. After 3 months, when the first workers emerged, the young colonies (reduced to a total of 42 colonies) were randomly spaced intraspecifically. We also followed the spatial patter of queens with respect to established colonies of both species. Queens founded nests away from the nests of all established colonies on the site. After three months, the young colonies were dispersed away from conspecifics only. During June through August 1986, we censused the number of foragers at the surviving V. pergandei nests. Young colonies that were more active also tended to be far from established conspecifics in July and August. There was no correlation of forating activity with distance to heterospecific established colonies in any month. These results indicate that established conspecifics may reduce the survivorship of young ant colonies.
Neurosecretion and Granules in Neurones of the Brain of the Leech

EXAMINATION of established neurosecretory strucfores with the electron microscope reveals characteristic cytoplasmic structures: the elementary neurosecretory granules. These granules are usually electron-dense and range in diameter from about 1000 A. to about 3000 A. Mean granule diameters differ from cell to cell in the same and in different species; but the fully formed granules are of relatively constant size for each cell type.
Inverse Source Solver for a High Resolution Near Field Scanner in Microelectronic Applications

A potential application of inverse source solver for high resolution near field scanning of microelectronic packages is studied in this paper. A fast inverse source solver based on the fast Fourier transform algorithm and conjugate gradient algorithm is developed with a half-space Green's function. This solver can be used in microelectronic applications to solve radiation related problems, including electromagnetic interference and signal integrity of printed circuit boards or integrated circuit packagings. Simulation results show a significant improvement in image resolution and adjacent sources detectability when the inverse source solver is applied. Because of the improvements, the inverse source solver reduces the sensitivity on scan height in the near field scan process when the same source image resolution is desired. Experiments on measured data also validate the effectiveness of this solver.
Hydrogen ion activity in dental plaques of hamsters during metabolism of sucrose, glucose and fructose

Abstract Hamsters receiving a high sucrose diet were infected orally with strains of Streptococcus mutans , known to induce dental microbial plaque formation and caries in these animals, or a strain of Odontomyces viscosus , which causes the accumulation of plaque deposits in the gingival sulcus but does not induce coronal caries lesions. Glass micro-electrodes were used to follow the pH changes following the application of concentrated or dilute solutions of sucrose, glucose, or fructose to the plaques in situ . The hydrogen ion activity of Strep. Mutans -induced plaque deposits increased rapidly upon the application of carbohydrate solutions, readily attaining pH values of 5.0 or lower. Plaques formed as a result of O.viscosus infection produced acid at a slower rate and to a lesser extent (minimum pH 5.4, average 6.4). Plaque deposits resulting from the indigenous oral microflora were scanty and produced very little acid (minimum pH 5.8, average 7.0). The amount of carbohydrate applied and the size of the plaque also influenced the rate and extent of hydrogen-ion activity change. Fructose was fermented at a slightly slower rate than glucose or sucrose by the plaques of animals infected with Strep. mutans . However, the relative ability of these carbohydrates to serve as substrates for acid production did not correlate with their reported relative efficacy as cariogenic dietary substrates, indicating that additional factors are involved in the development of caries in the hamster.
Specificity of the ferrous oxidation of xylenol orange assay: analysis of autoxidation products of cholesteryl arachidonate

Autoxidation of polyunsaturated fatty acids and esters leads to a complex mixture containing hydroperoxides and cyclic peroxides. The oxidation mixture of cholesteryl arachidonate, which has been characterized by a variety of mass spectrometry techniques, was subject to analysis by conventional thiobarbituric acid-reactive substance (TBARS) and ferrous oxidation in xylenol orange (FOX) assays. Our results indicate that the FOX assay is not specific for hydroperoxides. Cyclic peroxides, such as monocyclic peroxides and serial-cyclic peroxides, give a positive FOX response even after triphenylphosphine reduction. We suggest that bicyclic endoperoxides are the major TBARS active compounds present in cholesteryl arachidonate oxidation mixtures. These compounds give a positive FOX assay before reaction with triphenylphosphine but negative TBARS and FOX assays after this reaction. Caution should be exercised when the FOX assay is used to analyze highly oxidized lipids, especially arachidonyl-containing lipids.
Surface impedance of a three layer earth with a thin intermediate conducting layer

The thin sheet representation for a conducting layer is investigated for a three layer earth model with reference to magnetotelluric theory. The exact surface impedance is found for the three layer model and then it is compared to the surface impedance for the case when the second layer is assumed to be infinitesimally thin with a conductivity which is infinitely large. It is found that the thin sheet idealization is valid if the layer thickness is small compared with the skin depth of the layer material. The results are relevant to the sub-surface probing of saline layers.
Stimulating Energy Conservation by Sharing the Savings: A Community-Based Approach

In this paper a novel shared-savings approach to residential energy conservation is evaluated. By the use of data on preretrofit and postretrofit energy consumption, a normalization procedure to control for weather, and control groups, it is concluded that the shared-savings program (RECAP) has reduced annual electricity consumption by 1556 kWh per household, or 6.6% of preretrofit consumption. Energy savings differ markedly across the four communities served by RECAP, and are only weakly associated with installation costs. Savings are greater where audits are used to select participants with significant potential for conservation; households with large preretrofit electricity consumption generate particularly large savings. Regression analysis of survey data suggests that the net impact of behavioral and household changes upon electricity savings is minimal.
Perceptions of the IEP Requirement

The Individuals with Disabilities Education Act mandates that free, appropriate, public education (FAPE) be provided to children with educationally-defined disabilities. The Individualized Educatio...
Nanomechanical Chemical Sensor Platform

For gas phase chemical sensing, we have developed a selective, sensitive and portable sensing platform, which integrates bio receptors, chemo-mechanical sensor array, and electrical readout circuits. The biggest challenge in chemical sensors is selectivity of a receptor to its respective target molecule against a background of various interfering agents. For target specific receptors, sequence-specific recognition motifs have been identified through directed evolution methods, called phage display. We have demonstrated and updated a parylene micromembrane surface stress sensor array which uses capacitive signal readout. For a fully integrated sensor platform, a portable chemical sensing board has been built.
The tropopause and the thermal stratification in the extratropics of a dry atmosphere

A dynamical constraint on the extratropical tropopause height and thermal stratification is derived by considerations of entropy fluxes, or isentropic mass fluxes, and their different magnitudes in the troposphere and stratosphere. The dynamical constraint is based on a relation between isentropic mass fluxes and eddy fluxes of potential vorticity and surface potential temperature and on diffusive eddy flux closures. It takes baroclinic eddy fluxes as central for determining the extratropical tropopause height and thermal stratification and relates the tropopause potential temperature approximately linearly to the surface potential temperature and its gradient. Simulations with an idealized GCM point to the possibility of an extratropical climate in which baroclinic eddy fluxes maintain a statically stable thermal stratification and, in interaction with large-scale diabatic processes, lead to the formation of a sharp tropopause. The simulations show that the extratropical tropopause height and thermal stratification are set locally by extratropical processes and do not depend on tropical processes and that, across a wide range of atmospheric circulations, the dynamical constraint describes the relation between tropopause and surface potential temperatures well. An analysis of observational data shows that the dynamical constraint, derived for an idealized dry atmosphere, can account for interannual variations of the tropopause height and thermal stratification in the extratropics of the earth's atmosphere. The dynamical constraint implies that if baroclinic eddies determine the tropopause height and thermal stratification, an atmosphere organizes itself into a state in which nonlinear interactions among eddies are inhibited. The inhibition of nonlinear eddy–eddy interactions offers an explanation for the historic successes of linear and weakly nonlinear models of large-scale extratropical dynamics.
The Ins and Outs of DNA Fingerprinting the Infectious Fungi

DNA fingerprinting methods have evolved as major tools in fungal epidemiology. However, no single method has emerged as the method of choice, and some methods perform better than others at different levels of resolution. In this review, requirements for an effective DNA fingerprinting method are proposed and procedures are described for testing the efficacy of a method. In light of the proposed requirements, the most common methods now being used to DNA fingerprint the infectious fungi are described and assessed. These methods include restriction fragment length polymorphisms (RFLP), RFLP with hybridization probes, randomly amplified polymorphic DNA and other PCR-based methods, electrophoretic karyotyping, and sequencing-based methods. Procedures for computing similarity coefficients, generating phylogenetic trees, and testing the stability of clusters are then described. To facilitate the analysis of DNA fingerprinting data, computer-assisted methods are described. Finally, the problems inherent in the collection of test and control isolates are considered, and DNA fingerprinting studies of strain maintenance during persistent or recurrent infections, microevolution in infecting strains, and the origin of nosocomial infections are assessed in light of the preceding discussion of the ins and outs of DNA fingerprinting. The intent of this review is to generate an awareness of the need to verify the efficacy of each DNA fingerprinting method for the level of genetic relatedness necessary to answer the epidemiological question posed, to use quantitative methods to analyze DNA fingerprint data, to use computer-assisted DNA fingerprint analysis systems to analyze data, and to file data in a form that can be used in the future for retrospective and comparative studies.
Definitive hematopoiesis requires Runx1 C-terminal-mediated subnuclear targeting and transactivation

Runx1 is a key hematopoietic transcription factor required for definitive hematopoiesis and is a frequent target of leukemia-related chromosomal translocations. The resulting fusion proteins, while retaining DNA binding activity, display loss of subnuclear targeting and associated transactivation functions encoded by the C-terminus of the protein. To define the precise contribution of the Runx1 C-terminus in development and leukemia, we created a knock-in mouse with a C-terminal truncation by introducing a single nucleic acid substitution in the native Runx1 locus. This mutation (Runx1(Q307X)) models genetic lesions observed in patients with leukemia and myeloproliferative disorders. The Runx1(Q307X) homozygous mouse exhibits embryonic lethality at E12.5 due to central nervous system hemorrhages and a complete lack of hematopoietic stem cell function. While able to bind DNA, Runx1(Q307X) is unable to activate target genes, resulting in deregulation of various hematopoietic markers. Thus, we demonstrate that the subnuclear targeting and transcriptional regulatory activities of the Runx1 C-terminus are critical for hematopoietic development. We propose that compromising the C-terminal functions of Runx1 is a common mechanism for the pathological consequences of a variety of somatic mutations and Runx1-related leukemic fusion proteins observed in human patients.
[“Comment on ‘Further suggestions for writing memorable geophysical papers’”] More of the same”but different

In an earlier Forum piece, D. N. Baker (Eos, September 10, 1985, p. 642) complained that AGU members had not heeded his earlier call (Eos, December 21, 1982, p. 1219) to form author teams to write “memorable” geophysical research papers.
On the Elastic Assumption for Copper Lines in Interconnect Stress Modeling

Finite element modeling of thermal stresses in copper (Cu) interconnect lines is carried out to examine the effect of input material model on the stress-temperature output. This paper is motivated by the near-linear response of experimentally measured stress in passivated Cu lines as a function of temperature, which often drew the conclusion that Cu lines behave only elastically. In the present analysis, a purely elastic Cu and an elastic-plastic Cu are employed in the interconnect structure containing the metallization, the barrier layers, and the dielectric. Thermal cycling between 20degC and 350degC is simulated. It is shown that both material models for Cu yield similar stress-temperature histories. However, with consideration of available experimental observations and further numerical analyses, it is shown that the elastic-plastic nature of Cu lines needs to be taken into account in interconnect stress modeling. Select simulation results on Cu interconnect/low-k dielectric systems are also presented.
On-chip detection of non-classical light by scalable integration of single-photon detectors

United States. Army Research Office (Defense Advanced Research Projects Agency. Information in a Photon (InPho) Program Grant W911NF-10-1-0416)
Delay regulation: a circuit solution to the power/performance tradeoff

This paper introduces the concept of delay regulation as a means of controlling circuit delay variations from chip to chip, which is especially important in VLSI products. An embodiment of this concept which applies a phase-locked loop to individually control chip performance and power is presented together with computer-simulated results of an example design. It is shown that accurate delay equations and the potential for improved product yield result from application of the concept. The circuit overhead for large circuits is shown to be negligible. Application to a wide range of logic circuit types is also described.
Intergroup Aggression in Primates and Humans: The Case for a Unified Theory

Human warfare and intergroup aggression among primates have traditionally been considered to be largely unrelated phenomena. Recently, however, chimpanzee intergroup violence has been proposed to show evolutionary continuities with war among small-scale societies because both systems involve interactions among temporary subgroups, deliberate attempts to hunt and maim, and demographically significant death rates. Here, we ask whether the functional similarities between intergroup aggression among humans and chimpanzees can be extended to troop-living primates. In most primates, patterns of intergroup aggression involve brief encounters among stable troops, rare violence, and almost no killing. Although they, therefore, show little behavioral resemblance to warfare, growing evidence indicates that intergroup dominance is adaptively important in primates because it predicts long-term fitness. This suggests that in all primates, including humans, individuals use coalitions to maintain or expand access to resources by dominating their neighbors. Thus, while the style of coalitionary aggression depends on each species’ evolutionary ecology, we propose that the essential functional reasons for intergroup competition are consistent across group-living primates and humans: strength in numbers predicts long-term access to resources.