cssi/SciSciGPT-SciSciNet huggingface dataset:
Realizing an 802.11-based covert timing channel using off-the-shelf wireless cards

By using covert channels, a malicious entity can hide messages within regular traffic and can thereby circumvent security mechanisms. This same method of obfuscation can be used by legitimate users to transmit messages over hostile networks. A promising area for covert channels is wireless networks employing carrier sense multiple access with collision avoidance (CSMA/CA) (e.g., 802.11 networks). These schemes introduce randomness in the network that provides good cover for a covert timing channel. Hence, by exploiting the random back-off in distributed coordination function (DCF) of 802.11, we realize a relatively high bandwidth covert timing channel for 802.11 networks, called Covert-DCF. As opposed to many works in the literature focusing on theory and simulations, Covert-DCF is the first fully implemented covert timing channel for 802.11 MAC using off-the-self wireless cards. In this paper, we introduce the design and implementation of Covert-DCF that is transparent to the users of the shared medium. We also evaluate the performance of Covert-DCF and provide discussions on the feasibility of this technique in a real world scenario.
The Chicago Guide to Communicating Science

Frankly, I was offended at the outset by two things about this book: the title and the blurb about the author. It is one thing for the Chicago Press to put out a book on the technical details of style. After all, someone has to layout more than anyone would ever possibly need to know on the exactitudes of how to quote, reference, and punctuate. But what on Earth could Chicago ever tell us about how to write, review, and illustrate a scientific paper, proposal, or technical report? And, even more, what do they know about giving a riveting talk? Would this be the Midwestern version of how to present science? Will rival accounts follow from California, Massachusetts, and England? Who should we take seriously about something at which we already take ourselves to be masterful?
Epithelial neoplasms of the vermiform appendix (exclusive of carcinoid). I. Adenocarcinoma of the appendix

A study of primary epithelial neoplasms of the appendix (with the exception of classical carcinoids), produced 24 adenocarcinomas and 42 benign lesions from the files of the Laboratory of Surgical Pathology of Columbia University. Invasive adenoarcinomas were often complicated by appendicitis and were then unexpectedly discovered during appendectomy. In one third of the cases the carcinomas were found in juxtaposition to adenomatous lesions of the appendix. Well-differentiated adenocarcinomas of the colonic type generally had a better prognosis than signet-ring cell (or microglandular) tumors. The most reliable criterion for correlating prognosis was the Duke's method of staging. Since invasive adenocarcinomas of the appendix can metastasize to regional lymph nodes, treatment should ideally consist of ileocolectomy.
Defining the sources of Paradox: DNA sequence markers for North American walnut (Juglans L.) species and hybrids

Abstract One of the most important rootstocks in the California walnut industry is Paradox, which refers to the offspring of a California black walnut pollinized by a Persian walnut ( Juglans regia ). Paradox was developed by Luther Burbank, who did not distinguish between northern ( J. hindsii ) and southern ( J. californica ) California black walnut. Although it is generally accepted that Paradox designates hybrids between J. hindsii and J. regia , the name is commonly applied to any black walnut–Persian walnut hybrid. Moreover, due to gene flow among black walnut species, the genealogy of Paradox hybrids may also include species such as Arizona ( J. major ) and Eastern black ( J. nigra ) walnut. Since the nuts from which Paradox seedlings are grown are collected from wild trees, their genetic backgrounds are not generally known. In conjunction with a large study aimed at evaluating Paradox hybrids from different industry sources, we have been working to develop molecular markers that can be used to infer the parentage of individual Paradox seedlings. Representatives of the five black walnut species from North America were screened for variability in the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA and in three noncoding regions from the chloroplast genome, the trn T– trn L, trn L– trn F, and trn D– trn T spacers. Unique sequence markers were identified for each species, and total DNA extracts from 27 Paradox source trees were tested for those markers. Chloroplast DNA profiles were used to trace the maternal lineages of the Paradox source trees, while the ITS data provided evidence as to whether or not the source trees were themselves hybrids. Our results indicate that, among industry Paradox sources, there is considerable genetic contribution from species other than J. hindsii .
ALTERNATIVE ARRANGEMENTS FOR COST EFFECTIVE POLLUTION ABATEMENT: THE NEED FOR IMPLEMENTATION ANALYSIS

After examining policies and proposals designed to achieve cost-effective pollution abatement, the authors argue that design of economically elegant solutions to pollution control problems needs implementation analysis if the policies are to be successfully carried out. They review some institutional obstacles to implementation and conclude that these impediments should not prevent adoption.
Health of the American Indian: Papago Children

The health of the American Indian is a matter of increasing concern. The availability of extensive lineage records, the preservation of traditional cultural factors and the relative absence of miscegenation characterize the Papago tribe of southwestern Arizona. A complete cohort of 134 full-bloodd Papago children born between July 1965 and December 1967 and living on reservation were studied with their families. In addition over 900 school children from all parts of the reservation were examined. The survival of the Papago is dependent upon cultural patterns adaptive in the arid environment of the Southwest. However, this culture carries with it other, less desirable, consequences including (1) a high frequency of several congenital malfromations (myelodysplasia and microphthalamia) due to endogamous marriage practices, (2) high mortality and morbidity from infectious disease, (3) normal perinatal development followed by growth retardation, and (4) the early onset of obesity and a high frequency of diabetes mellitus. This study has suggested modifications of the health care system more compatiable with the cultural setting which will lessen the adverse impact of these adaptations on Papago children.
Eye tracking, schizophrenic symptoms, and schizotypal personality disorder

Schizophrenic patients and patients with schizotypal personality disorder were significantly more likely than normal controls to demonstrate impaired eye tracking performance. Fifteen of 27 schizophrenics and 15 of 27 schizotypals had impaired eye tracking, compared with 11 of 39 normal controls. In the schizophrenic group, including 10 out-patients in a stable state of relative remission, impaired eye tracking was associated with more severe formal thought disorder and more time spent in psychiatric hospitals. Among stable schizophrenic out-patients, poor eye tracking was related to more severe formal thought disorder and greater overall psychopathology. This pattern of results suggests a possible relation between eye tracking impairment and more severe enduring symptoms across the spectrum of schizophrenic and schizophrenia-related disorders.
Comparing speaking across the curriculum and writing across the curriculum programs

Speaking (or oral communication) across‐the‐curriculum programs sometimes mirror approaches taken by the writing across‐the‐curriculum movement. To establish themselves as valuable curricular enterprises in their own right, speaking across‐the‐curriculum programs must articulate the unique philosophical and pedagogical contributions they offer. This essay explores the similarities and differences between writing and speaking across the curriculum programs in three areas‐the foundation experience, program objectives, and notions about process. The essay focuses more on differences than similarities, for careful examination of differences may aid speaking across the curriculum advocates in adding meaningfully to the theory and pedagogy of the language across‐the‐curriculum concept.
Thrombophlebitis and genital carcinoma in women.

In a study of 1217 women with various kinds of genital carcinoma, 43 had thrombophlebitis of the lower extremities that either preceded the diagnosis of the tumor or complicated the clinical course after the diagnosis and/or treatment. All but four patients have died at this reporting. Of those dead, more than a half succumbed within 6 months after the thrombophlebitis appeared, the remainder died within 26 months. Those who lived were those in whom the tumor had been completely removed or its growth curtailed. In general, thrombophlebitis is a bad prognostic sign. Its appearance is associated with presumably a hypercoagulant response of the blood. Occasionally, the thrombophlebitis is associated with spread of the tumor into the local venous channels. It is often associated with lymphedema. If the patient acquires thrombophlebitis and lives long enough, both extremities may become involved. Therapeutic measures should be directed toward removal or destruction of the neoplasia. Otherwise the treatment for the thrombophlebitis will usually be unsuccessful.
Accurate Pair Interaction Energies for Helium from Supermolecular Gaussian Geminal Calculations

Nonrelativistic clamped-nuclei pair interaction energy for ground-state helium atoms has been computed for 12 interatomic separations ranging from 3.0 to 9.0 bohr. The calculations applied the supermolecular approach. The major part of the interaction energy was obtained using the Gaussian geminal implementation of the coupled-cluster theory with double excitations (CCD). Relatively small contributions from single, triple, and quadruple excitations were subsequently included employing the conventional orbital coupled-cluster method with single, double, and noniterative triple excitations [CCSD(T)] and the full configuration interaction (FCI) method. For three distances, the single-excitation contribution was taken from literature Gaussian-geminal calculations at the CCSD level. The orbital CCSD(T) and FCI calculations used very large basis sets, up to doubly augmented septuple- and sextuple-zeta size, respectively, and were followed by extrapolations to the complete basis set limits. The accuracy of the total interaction energies has been estimated to be about 3 mK or 0.03% at the minimum of the potential well. For the attractive part of the well, the relative errors remain consistently smaller than 0.03%. In the repulsive part, the accuracy is even better, except, of course, for the region where the potential goes through zero. For interatomic separations smaller than 4.0 bohr, the relative errors do not exceed 0.01%. Such uncertainties are significantly smaller than the expected values of the relativistic and diagonal Born-Oppenheimer contributions to the potential.
Mitral valve reconstruction versus replacement for degenerative or ischemic mitral regurgitation.

Abstract Between January 1985 and June 1992 263 consecutive patients had mitral valve reconstruction (133 patients) or replacement (130 patients) for degenerative or Ischemic mitral regurgitation. The two groups were similar in sex, age, prior infarctions or cardiac operations, hypertension, angina, and functional class. Both groups were similar in mean ejection fraction, pulmonary artery pressure, cardiac index, and incidence of coronary artery disease. More reconstruction than replacement patients had ischemic etiology (22 [16%] versus 12 [9%]; p = not significant), and fewer reconstruction patients had ruptured anterior leaflet chordae (9[7%] versus 39[30%]; p p = not significant). Hospital death occurred in 4 reconstruction patients (3%) and 15 (12%) replacement patients ( p p = 0.02). Late valve-related death occurred in 3 reconstruction patients (2%) and 8 (6%) replacement patients ( p = 0.08). Six-year actuarial freedom from thromboembolism was 92% for the reconstruction group and 85% for the replacement group ( p = 0.12). Freedom from all valve-related morbidity and mortality was 85% for the reconstruction patients and 73% for the replacement patients ( p = 0.03). Significant multivariate predictors of hospital death were age, mitral valve replacement, functional class, congestive heart failure, no posterior chordal rupture, and nonelective operation. Mitral valve reconstruction, when technically feasible, is the procedure of choice for degenerative or ischemic mitral regurgitation because of significantly lower hospital mortality and late valve-related events.
Severity of scapholunate instability is related to joint anatomy and congruency.

Purpose To determine whether the bony architecture of the distal radius and proximal scaphoid have a role in stabilizing the scaphoid, and to determine whether a relationship between the bony geometry measurements and the amount of wrist constraint could be determined. Methods Eight cadaver wrists were tested in a wrist joint motion simulator. The level of scapholunate instability after sectioning the scapholunate interosseous, radioscaphocapitate, and the scaphotrapezium ligaments was determined and related to radiographic measurements of volar tilt, lateral tilt (ulnar tilt of the radioscaphoid fossa), the depth of the radioscaphoid fossa, and 6 radii of curvature measurements of the proximal scaphoid and distal radius. The force to dorsally dislocate the scaphoid out of the radioscaphoid fossa was computed. Results The radioscaphoid fossa and scaphoid curvatures were larger in those wrists that did not show gross instability after ligamentous sectioning in the wrist simulator. Similarly, those wrists with a deeper radioscaphoid fossa and greater volar tilt were also more stable. The force required to dislocate these wrists was greater than in those wrists that showed gross carpal instability. Conclusions This study suggests that the bony anatomy of the radius and scaphoid have a role in stabilizing the carpus after ligament injury. The effect of ligament sectioning on producing carpal instability may be moderated by the bone geometry of the radiocarpal joint. This may explain why some people may have a tear of the scapholunate interosseous ligament but not present with clinical symptoms.
Sternal Odors as Cues for Social Discrimination by Female Virginia Opossums, Didelphis virginiana

The role of secretions of sternal scent glands in social recognition was examined in captive adult female Virginia opossums, Didelphis virginiana . Five of six females directed significantly more investigative behavior toward plastic disks artificially scent marked with sternal odors from male conspecifics than toward those marked with sternal odors from females when odors were presented in paired male-female combinations. None investigated female odors more than those of males. Estrous status did not appear to influence responses to sternal odors. Subjects also demonstrated the ability to discriminate between individual odors of females presented in pairs, even though females lack the specialized sternal glands characteristic of males. No evidence was found for an ability of female opossums to discriminate among odors of individual males.
Three dimensional hydrodynamic modeling over bed forms in open channels

Abstract Three dimensional numerical modeling of idealized sand dunes was used to assess the capability of various modeling formulations to capture the flow structure and resistance introduced by bed forms which are similar to those in the Lower Mississippi River. The selected models were: ECOMSED (HydroQual), MIKE 3 [Danish Hydraulic Institute (DHI)] and H3D (Hayco). The study revealed that the hydrostatic versions of models did not capture the flow separation at the crest of the dunes; however, they did respond to the presence of bed forms and gave a total resistance similar to the non-hydrostatic models.
Becoming Students and Becoming Ethnographers in a Preschool

Abstract Preschool poses unique schooling demands which challenge young children to become young students. This distinctive socialization process is the research problem addressed in an ethnography of a preschool classroom. The introduction details practical considerations which suggest the distinctiveness and importance of early education and of children's socialization to it. The first major section presents an integration of relevant socialization theories and a discussion of ethnography as a research perspective. In the next section, the ethnographic research procedures used in the study are explained generally. In a final section, a conceptualization of this preschool classroom as a dynamic configuration of school culture and peer culture (Corsaro, 1985) is proposed, serving as hypothesis and heuristic tool for ongoing research.
Synthesis of tritiated cromolyn diethyl ester

We report here the synthesis of tritiated cromolyn diethyl ester of high specific activity and acceptable stability for use in in vitro and in vivo models of experimental asthma in the guinea pig. Preparation of an aryl brominated precursor, 1,3-bis-(2-acetyl-3-hydroxy −6-bromophenoxy)-2-propanol, followed by catalytic debromination with tritium gas and two subsequent synthetic steps atforded tritiated cromolyn diethyl ester with a specific activity of 135 mCi/mg (71 Ci/mmol).
Assessing Presidential Power: Signing Statements and Veto Threats as Coordinated Strategies

Presidents have a wide array of strategies to influence legislation. One area that has seen less emphasis in the literature is the executive's unilateral ability to issue signing statements and their role in shaping policy. We develop a spatial model illustrating how the president's bargaining power with Congress can be expanded when the veto threat is coordinated with signing statements. The analysis suggests that signing statements, although underappreciated, may potentially be a valuable presidential tool in the veto bargaining process. The analysis also shows that veto threats are a key factor explaining the president's use of the constitutional signing statement. We infer that veto threats and signing statements are linked together as part of a larger coordinated strategy to exert presidential power in the legislative realm.
Aircraft Spacings That Produce Vortex-Free Region Below Flight Formations

A preliminary theoretical study is presented of a concept whereby the vortex wakes shed by a formation of aircraft can be redirected to produce a large region below the formation that is free of vortices. The redirection of the vortices is accomplished by e rst spacing the aircraft so that vortex pairs are formed between the wingtips of adjacent aircraft. If the aircraft spacings are within certain limits that are presented in the analysis, the selfinduced velocity e eld of the vortex pairs causes all of the inboard vortices to move upward rather that downward. Oneapplication for such a process is the deployment of paratroopers from aircraft so that, while descending to the ground, no parachute will come near the lift-generated vortices shed by the deploying, or other nearby aircraft. The purpose of the study is to e nd out whether spacings between aircraft in a formation can be established so that thelift-generated vorticesbeing trailed moveupward ratherthan downward. Because thevorticesshed by a single aircraftmustalwaysdescend,attention wasfocused on multipleaircraftformations. Itwasfoundthatthemethodis feasibleand makesit possibleto arrangecloseformationsofaircraftso thatalloftheinboard trailing vorticesmove upward rather than downward. The two outboard vortices then travel downward at a greatly reduced velocity that depends on the number of aircraft in the formation. All of the inboard region below the formation is then free of vortices. The stability of spacings between aircraft in successful formations and the instrumentation required for implementation of the concept introduced are not treated.
Endwall heat transfer in the junction region of a circular cylinder normal to a flat plate at 30 and 60 degrees from stagnation point of the cylinder

The objective of this experimental study was to investigate the influence of horseshoe vortex on the heat transfer on a flat plate near the base of a protruding cylinder. The partial shock reflection technique was used to produce the flow Mach number of 0.14 which simulated the mean inlet flow Mach number for the first stage vanes of the turbine after combustor. Fast response thin-film platinum heat gages were used to measure the heat transfer flux for radial distances of 0.75, 0.875, 1.0, 1.125 cylinder diameter. For a low Reynolds number of 20,000, r/D = 0.75, and angular location from the stagnation point = 60 deg, the maximum increase in the heat transfer rate with the cylinder was observed to be approximately 460 percent greater than without the cylinder. On the other hand, the increase in the heat flux for a high Reynolds number of 300,000 was approximately 70 percent greater. For the heat gages located along 30 deg and 60 deg angular locations from the stagnation point, the strong effect of the horseshoe vortex was observed in the junction region. The increase in the heat transfer rate depended on the type of boundary layer and on the boundary layer thickness ahead of the cylinder.
Theoretical studies on living systems in the absence of mechanical stress.

Abstract Small single cells should show little effect of weightlessness. Cells as large as 10 μ across should show some effect due to the redistribution of mitochondria or the nucleolus. It is probable that if there is such a thing as a “gravity receptor” in a cell, it is the nucleolus. Systems of cells in which relatively large objects, such as ribosomes, pass from cell to cell should show gravity effects. Quite extensive systems, such as plants which exceed 1 cm in length should have increased membrane permeability at the lower end. This effect could be greatly increased if each cell had many internal membranes. Experiments on weightlessness should also consider temperature as a variable.
Graphene Growth on SiC and Metal Surfaces by Solid Source Carbon Deposition

Graphene has been grown by direct deposition of carbon from solid sources on both SiC and Ta films on SiC in an MBE environment. Carbon fluxes were obtained from thermally evaporated C60 and from a heated graphite filament. The graphene films were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. Graphene films on Si-face SiC grown by carbon source MBE (CSMBE) were compared with graphene grown by the standard epitaxial graphene process using SiC thermal decomposition. CSMBE on SiC was found to grow at lower temperatures (1200°C) and to have fewer pits and a more uniform surface. Uniform graphene films were found to grow on Ta films after exposure to both carbon sources at 1200°C but Raman measurements showed no signs of graphene on films exposed to the same temperature without a carbon flux.
Exploring the use of new school buildings through post-occupancy evaluation and participatory action research

This paper presents the results of the development and testing of an integrated post-occupancy evaluation (POE) approach for teachers, staff, pupils and community members using newly constructed school buildings. It focusses on three cases of UK secondary schools, demonstrating how users can be inspired to engage with the problems of school design and energy use awareness. The cases provided new insights into the engagement of school teachers, staff and young people regarding issues of sustainability, management, functional performance and comfort. The integrative approach adopted in these cases provided a more holistic understanding of these buildings’ performance than could have been achieved by either observational or more traditional questionnaire-based methods. Moreover, the whole-school approach, involving children in POE, provided researchers with highly contextualised information about how a school is used, how to improve the quality of school experiences (both socially and educationally) and how ...
Delayed Developmental Sequences in Rodent Diabetic Embryopathy

ABSTRACT: Diabetes induced by alloxan at day 6 of gestation in Wistar rats produced decreased fetal growth, delayed skeletal ossification, decreased fetal kidney β-glucuronidase, and an increased frequency of fetal birth defects which correlated with the degree of diabetic control. Offspring of severely diabetic mothers (mean blood glucose >501 mg/dl) sacrificed at 20 days had a mean weight of 2.12 ± 0.16 g, a mean of 1.8 ± 0.46 caudal ossification centers, and a 28% incidence of birth defects as compared to 3.70 ± 0.22 g, 5.9 ± 0.42 caudal centers, and 1.1%defects for controls. Offspring of severely diabetic mothers sacrificed at 21 days had mean numbers of caudal and sternal ossification centers which did not significantly differ from controls, indicating that decreased ossification observed at 20 days of gestation is a delayed developmental sequence which is mostly corrected by 21 days. Offspring of moderately diabetic (mean blood glucose 300-500 mg/ dl) and insulin-treated dams (mean blood glucose 152-168 mg/dl) had intermediate degrees of growth or ossification delay and birth defect frequency at both the 20- and 21- day sacrifices. Maternal diabetes also retards the developmental increase in fetal kidney β-glucuronidase such that 20-day offspring of severely diabetic mothers had a mean specific activity of 1.1 nmol/min/mg compared to 3.0 nmol/min/mg for controls. The results support prior studies in rodents suggesting a progression of early growth delay, altered developmental sequences, and birth defects in diabetic pregnancy. This progression is suggested as a common teratogenic mechanism which has implications for evaluating analogous pregnancies in man.
Response of an experimental mammary carcinoma to fractionated x-irradiation with misonidazole and microwave hyperthermia

Abstract X/Gf mice bearing the MT2 mammary adenocarcinoma were subjected to 4,000 rad of X rays given either as a single dose, or five daily fractions of 800 rad. Additional experimental groups were treated with either short term localized microwave hyperthermia (LMH) (42.5°C for 25 min.), or the hypoxic cell radiosensitizer misonidazole (MISO) (0.67 mg/g bw), or both hyperthermia plus MISO with X rays. The combined use of MISO plus 42.5°C with X rays was superior to the other treatment regimens as assessed by tumor regrowth delay and mean survival time. However, for the five fraction schedule, the addition of MISO plus hyperthermia was not as effective as observed for the single dose treatment. This may be attributed to reoxygenation of the hypoxic tumor cells between treatment fractions. MISO retention in tumor tissue under ambient and hyperthermic conditions was studied. The application of heat locally to the tumors caused a significant increase in MISO tumor concentration. However, after four X ray fractions the influence on MISO concentration by hyperthermia in the tumors could not be demonstrated. This may be related to the stromal damage by X rays in the tumor. tissue that was observed histologically.
A nonhuman primate's perception of object relations: experiments on cottontop tamarins, Saguinus oedipus

Abstract Objects in nature often have spatial and functional relationships with other objects. For example, fruit may be connected to tree branches, bushes sometimes function as landmarks for home, and stones are functionally associated with nuts when they are used to crack the nuts open. Although animals may use the spatial and functional relationships between specific objects, it is important for ethologists interested in cognitive mechanisms to ask whether animals understand the spatial relationship between objects in a more general and abstract way. In this experiment, we ask whether a small New World monkey, the cottontop tamarin, is capable of perceiving the abstract relational concept of ‘connectedness’. Using a traditional operant paradigm, subjects were required to press one button to images with connected objects, and another button to images with separated objects. In Phase 1 of the experiment, subjects received training with only one connected and one separated image. Following training, probe images were presented in which features such as colour, texture and shape were systematically manipulated to determine which features were more important in stimulus classification. Accuracies and reaction times of responses were recorded. On the basis of their performance, the tamarins appeared to recognize that changes in the colour or texture of two objects plays no functional role in determining whether such objects are connected or separated. In contrast, changes in the shape and distance between two objects does play an important functional role, and the tamarins appeared to be sensitive to such changes. In Phase 2, subjects received training with a larger set of images. After this training, classification accuracy remained significantly above chance with most probes, suggesting that the tamarins had acquired a more general connectedness concept. In Phase 3, novel images were presented. Classification accuracy was significantly above chance for many of the novel images. Overall, results suggest that tamarins perceive spatial relationships between stimuli to some extent and can classify images based in part on their spatial relationship. Other recent experiments have shown that cottontop tamarins respond to spatial relationships even better than in the current experiment when they have to act directly on the objects. The difference between these results suggests that tamarins perceive the spatial relationships between objects more readily in the context of an ecologically valid problem.
Piezoelectric Scattering in Semiconductors

The theory of the scattering of electrons by acoustic modes in piezoelectric semiconductors is generalized so as to properly take account of the anisotropic scattering probability. The Herring-Vogt approximate solution to the Boltzmann equation is used, which is accurate if the resulting relaxation-time tensor components do not differ by more than a factor of two or so. The other main simplifying assumption consists of treating the frequencies and polarizations of the acoustic modes by a simple approximation. The theory is applied to three symmetry classes of known piezoelectric semiconductors: zincblende and wurtzite symmetry (as typified by the III-V and II-VI compounds) and $\ensuremath{\alpha}$-quartz symmetry (as typified by selenium and tellurium). The electron mobility anisotropy calculated for CdS (based on the measured electroelastic properties and cyclotron-resonance masses) agrees quite well with the value deduced from experiment.
The stability of coronal loops - Finite-length and pressure-profile limits

Results are described from a quickly converging, necessary-and-sufficient, MHD-stability test for coronal-loop models. The primary stabilizing influence arises from magnetic line tying at the photosphere, and this end conditions requires a series expansion of possible loop excitations. The stability boundary is shown to quickly approach a limit as the number of terms increases, providing a critical length for the loop in proportion to its transverse magnetic scale. Several models of force-free-field profiles are tested and the stability behavior of a localized current channel, embedded in an external current-free region, is shown to be superior to that of other, broader, current profiles. Pressure-gradient effects, leading to increased or decreased stability, are shown to be amplified by line tying. Long loops must either conduct low net current, or exhibit an axial-field reversal coexisting with a low-pressure core. The limits on stability depend on the magnetic aspect ratio, the plasma-to-magnetic pressure ratio, and the field orientation at the loop edge. Applications of these results to the structure of coronal loops are described.
The membrane integration of a naturally occurring α-helical hairpin

Abstract Helical hairpins, two closely spaced helical membrane spanning segments separated by a short surface turn, are thought to be common in integral membrane proteins. Here, we study the membrane integration of a naturally occurring helical hairpin from the secretory Na+–K+–2Cl− cotransporter NKCC1. This sequence is only slightly longer and significantly less hydrophobic than a previously identified minimal poly-leucine model hairpin structure. Using site directed mutagenesis we document the importance of the turn propensity of the amino acids in the intervening surface turn but, somewhat surprisingly, our results indicate that the formation of this natural hairpin apparently does not depend on specific helix–helix interactions. Our results suggest that helical hairpins may be formed quite readily from even minimally hydrophobic sequences separated by a short, sufficiently strong, turn signal, and that current methods for predicting integral membrane protein topology may miss many similar short helical hairpin sequences. Thus the occurrence of these structures may be much more common than presently thought.
Characteristics of electromagnetic Rayleigh‐Taylor modes in nighttime equatorial plasma

[1] The unstable Rayleigh-Taylor plasma modes that are believed to be responsible for the density irregularities in the nighttime F region equatorial ionosphere have been studied before by assuming that the modes are electrostatic. In this paper, these plasma modes are studied without such assumption in order to determine the strength and the characteristics of the magnetic field fluctuations and to determine the physical condition under which the electrostatic assumption is justified. It is found that the relevant magnetic field fluctuations (ρ), which arise from the fluctuating parallel (to B0) current density, are associated with the shear Alfven waves. The parameter that determines the amplitude of ρ is α(s) ≡ Dm(s)k𝛗2/γ, where Dmk𝛗2 represents the rate at which magnetic field fluctuations with perpendicular wavelength λ𝛗(≡ 2π/k𝛗) diffuse away due to parallel resistivity and γ is the rate at which the fluctuations grow. Typically, α ≫ 1 in the equatorial ionosphere, which means that the excited magnetic field fluctuations diffuse at a rate much faster than their growth rate and, consequently, their amplitudes remain very small (compared to B0). Thus the Rayleigh-Taylor modes in the equatorial ionosphere are predominantly electrostatic in nature, and the electrostatic assumption of the previous analyses is quite justified. If the maximum amplitude of the electric field fluctuations (𝛗) is taken to be 1 mV/m, then the maximum amplitude of ρ is found to be less than 0.2 nT when λ𝛗 is 500 m, and it increases to about 2.4 nT when λ𝛗 is 20 km. Longer wavelength modes have somewhat larger magnetic field fluctuations, but their growth rates are smaller. While the maximum amplitude of 𝛗 occurs at the magnetic equator, that of ρ occurs at a distance away from it.
Synthesis and evaluation of potential Nπ and Nσ metal chelation sites within the β-hydroxy-l-histidine subunit of bleomycin A2: Functional characterization of imidazole Nπ metal complexation

The synthesis and evaluation of 4 and 5, fully functionalized deglycobleomycin A2 (2) analogues incorporating an oxazole and a pyrrole in place of the beta-hydroxy-L-histidine imidazole, are detailed. The oxazole agent is only capable of Npi metal complexation through a form related to the N1-H imidazole tautomer of bleomycin A2 (1) while the pyrrole agent may potentially mimic the Nsigma metal complexation capabilities of the imidazole N3-H tautomer. Metal complexes (Fe-II, Fe-III) of 4 and 5 were found to cleave duplex DNA in the presence of O2 (Fe-II) or H2O2 (Fe-III). The oxazole agent 4 which is incapable of Nsigma metal chelation was found to behave analogous to, albeit slightly less effectively than, deglycobleomycin A2 resulting in the characteristic 5'-GC/5'-GT sequence selective cleavage of duplex DNA directly confirming that imidazole/oxazole Npi metal chelation is sufficient for functional reactivity. Importantly, the effective substitution of the oxazole O-1 for the histidine N-1 further illustrates that this group does not require deprotonation upon metal complexation, oxygen activation, or the ensuing oxidation reactions, that the functional bleomycin A2 tautomer is the imidazole N'-H tautomer, and that the imidazole N'-H functionality is not contributing to the polynucleotide recognition through H-bonding to the phosphate backbone or nucleotide bases. In contrast, the pyrrole agent 5 which is incapable of Npi metal chelation, but possesses the capabilities of functioning as a Nsigma metal donor was also found to cleave duplex DNA, but does so in a nonsequence selective fashion with a significantly reduced efficiency and a diminished double to single strand cleavage ratio both only slightly above that of background iron itself. These observations are analogous to those made with 3 which lacks the imidazole altogether and further support the observations that Nsigma coordination, not Npi coordination, of the imidazole is required for the functional activity of bleomycin A2.
Induction of coelomocyte proliferation by xenografts in the earthworm Lumbricus terrestris

Abstract The demonstration of immune phenomena in earthworms similar to those found in vertebrates provides evidence of a pervasive biological reaction to non-self throughout the phylogenetic spectrum. Similar relationships among evolutionary disparate organisms are found in other physiological systems (nervous, digestive, respiratory, etc.), as well as at the molecular level as seen in subcellular characteristics, genetic processes and biochemical pathways. Phylogenetically different species also underwent long periods of evolutionary adaptation to the environment in which they thrived, resulting in the development of specialized mechanisms to cope with foreign antigenic aggressors.
Effect of Ehrlich ascites tumor cells on mouse plasma lipoproteins

In two separate experiments, a total of 120 mice were divided into two equal groups, one a control and the other an experimental group which was injected with Ehrlich ascites tumor cells. In the first experiment, the plasma lipoprotein patterns were obtained by disc electrophoresis from 4 control and 4 Ehrlich ascites tumor cell-injected animals on the 1st, 3rd, 5th, 7th and 9th day after injection of the tumor cells. After the 3rd day of injection, the electrophoretic patterns from Ehrlich ascites tumor-bearing mice indicated a striking decrease in high-density lipoproteins and an elevation in low-density lipoproteins. In order to confirm these results, in a second experiment (40 control and 40 Ehrlich ascites tumor-bearing mice), the plasma high-density lipoproteins were isolated by electrophoretic elution and their phospholipid was determined. A significant decrease (70%, p<0.01) in high-density lipoprotein-phospholipid was observed after the 3rd day of injection in the plasma of tumor-bearing mice and suggested a relationship between the growth of tumor cells and plasma high-density lipoproteins.
Assessing the Quality of a Decision Support E-Service

Electronic service quality, or e-service quality, is the quality experienced by the user of a service delivered over the Web. Over the past several years, researchers have developed many models of e-service quality with the goal of identifying those factors that are most important for customer loyalty. Most of these models focus primarily or exclusively on retail e-commerce Web sites which support the delivery of a physical product to the consumer. Recently, however, "pure" e-service Web sites, namely those that do not involve the sale and delivery of a physical good, have received increasing attention from researchers. This article proposes and validates a quality assessment instrument for a type of pure e-service that has not yet been studied: a Web-based decision support system. Based on a study involving over six hundred subjects, we identify those quality dimensions that affect customer loyalty for a pure e-service of this type.
Heterojunction ion-implanted FETs (HIFETs)

Summary form only given. The authors report the enhanced microwave performance of ion-implanted MESFETs fabricated on graded GaAs-AlGaAs heterostructures. Since low-noise MESFETs are typically biased at a low drain current, optimum low-noise operation requires high f/sub 1/ at low drain currents. f/sub t/ values reported in the literature are generally measured close to I/sub dss/. This 0.5- mu m gate heterojunction ion-implanted FET (HIFET) exhibits enhanced microwave performance, especially at low drain current, when compared to conventional ion-implanted GaAs MESFETs. At 20% of I/sub dss/, the current gain cutoff frequency f/sub t/ is 40 GHz, which increases to 47 GHz at 50% of I/sub dss/. At 100% of I/sub dss/, the f/sub t/ is 41 GHz. The maximum stable gain at 25 GHz of the HIFET is also 4 dB higher than that of the conventional MESFET. >
A Novel Role for Cytochrome c: Efficient Catalysis of S-Nitrosothiol Formation

Although S-nitrosothiols are regarded as important elements of many NO-dependent signal transduction pathways, the physiological mechanism of their formation remains elusive. Here, we demonstrate a novel mechanism by which cytochrome c may represent an efficient catalyst of S-nitrosation in vivo. In this mechanism, initial binding of glutathione to ferric cytochrome c is followed by reaction of NO with this complex, yielding ferrous cytochrome c and S-nitrosoglutathione (GSNO). We show that when submitochondrial particles or cell lysates are exposed to NO in the presence of cytochrome c, there is a robust formation of protein S-nitrosothiols. In the case of submitochondrial particles protein S-nitrosation is paralleled by an inhibition of mitochondrial complex I. These observations raise the possibility that cytochrome c is a mediator of S-nitrosation in biological systems, particularly during hypoxia, and that release of cytochrome c into the cytosol during apoptosis potentially releases a GSNO synthase activity that could modulate apoptotic signaling.
The red nucleus of the opossum (Didelphis marsupialis virginiana): a light and electron microscopic study.

The opossum midbrain was sectioned in frontal, sagittal and horizontal planes and subsequently stained with cresyl violet to determine the cytoarchitecture of the red nucleus. The neurons were visualized in more detail in Golgi preparations, one micron plastic sections and by employing electron microscopy. Distinct parvicellular and magnocellular subdivisions are not apparent in this species. The characteristic neurons can be divided into three types by utilizing the following criteria: size, distribution of Nissl bodies and dendritic patterns. The cytoplasm of the giant neurons (45–70 μ) is filled with Nissl granules and the dendrites are long and tapered, and display an occasional spine. The large-medium neurons (40–25 μ) can be differentiated from the giant neurons on the basis of size and their less extensive pattern of dendritic branching. Small neurons (10–20 μ) are achromatic or have a uniformly basophilic cytoplasm and may be classified as Golgi type II neurons. The large-medium size neurons are the most numerous of the three types described and they are distributed throughout the entire extent of the nucleus. The small neurons, although found less frequently than the large-medium size cells, also are scattered throughout the nucleus. The giant neurons are limited to the caudal medial 0.5 mm of the nucleus. A morphological classification of synaptic terminals is described: (1) small (1–2 μ), (2) elongate (up to 10 μ), (3) boutons en passage and (4) large (2–4 × 5–9 μ). Differences in the population of synaptic vesicles in the four types of synaptic endings are described. In addition, differences in the distribution of the four types of synaptic terminals with respect to the soma, proximal dendrites and dendrites in the neuropil are illustrated.
Input-output analysis of energy requirements for short rotation, intensive culture, woody biomass

Abstract A production model for short rotation, intensive culture (SRIC) plantations was developed to determine the energy and financial costs of woody biomass. The model was based on hybrid poplars planted on good quality agricultural sites at a density of 2100 cuttings ha−1, with average annual growth forecast at 16 metric tonne, oven dry (Mg(OD)). Energy and financial analyses showed preharvest costs of 4381 megajoules (MJ) Mg−1 (OD) and $16 (U.S.) Mg−1 (OD). Harvesting and transportation requirements increased the total costs to 6130 MJ Mg−1 (OD) and $39 Mg−1 (OD) for the delivered material. On an energy cost basis, the principal input was land, whereas on a financial basis, costs were more uniformly distributed among equipment, land, labor, and materials and fuel.
The Therapeutic Potential of Bone Marrow Derived Stromal Cells

Since the replacement of the hematopoietic system became feasible through bone marrow (BM) transplantation, the idea of how to replace other organs of the body has been in the forefront of medical research. Scientists have been searching for the ideal stem cell that could be manipulated to differentiate into any tissue. Although the embryonal stem cells seemed to have the ability to do this, the difficulties surrounding their use prevented them from becoming therapeutically useful. Thus, the field turned to adult stem cells, particularly stem cells of BM origin. We have learnt a lot during the last decade about the potential of the BM-derived stromal (also called mesenchymal stem) cells (BMSCs). The first studies suggested them as cell replacement tools, but later it turned out that their usefulness is more likely due to paracrine effects due to a large variety of secreted factors that induce growth and differentiation of the tissue-specific stem cells as well as prevent injured cells from apoptotic death. Finally, a whole new field emerged when many groups confirmed that these cells are also capable of regulating immune function in a so far unknown, dynamic manner. When BMSCs are injected they seem to be able to sense the environment and respond according to the actual need of the organism in order to survive. This plasticity can never be done by the use of any drugs and such a “live” cell therapy could open a whole new chapter in clinical care in the future. J. Cell. Biochem. 112: 2683–2687, 2011. © 2011 Wiley-Liss, Inc.
Voltage-gated potassium channel-complex antibody-associated limbic encephalitis.

Limbic encephalitis is characterized by the subacute progression of short-term memory loss, disorientation, confusion, and agitation. Hallucinations, behavioral and personality changes, temporolimbic seizures, sleep disturbances, and dysautonomia may also occur. The pyramidal layer of the hippocampus and the amygdaloid nuclei are particularly susceptible and demonstrate neuronal loss, reactive gliosis, and perivascular lymphocytic cuffing. Magnetic resonance imaging (MRI) typically reveals increased signal in limbic structures on T2, fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI). Historically, limbic encephalitis has been conceptualized as a paraneoplastic process characterized by autoantibodies associated with underlying neoplasms: small cell lung, lymphoma, thymoma, testicular, breast, teratoma, prostate, rectal, retinoblastoma, oligodendroglioma, melanoma, and leiomyosarcoma. Although a definitive pathophysiologic mechanism for autoimmune limbic encephalitis remains unknown, multiple autoantibodies are implicated, including voltage-gated potassium channel complex antibodies (VGKC-complex Ab.) Idiopathic autoimmune limbic encephalitis also occurs. We present the longitudinal course of a man who developed cognitive and behavioral disturbances ultimately attributed to VGKC complex autoimmunity.