cssi/SciSciGPT-SciSciNet huggingface dataset:
Experimental Studies of Vapor-Deposited Water-Ice Films Using Grazing-Angle FTIR-Reflection Absorption Spectroscopy

Grazing-angle Fourier transform infrared reflection absorption spectroscopy was used to monitor the free OH stretch (or “dangling bond”) in vapor-deposited H2O−ice films between 94 and 120 K. Ice film thicknesses and the sensitivity of our instrument to water−ice molecules were determined by optical interference using a helium−neon laser. These calibrations indicate that the dangling bond signals observed in the present study are indicative of the surfaces of micropores present within the amorphous ice bulk. The largest dangling bond signal (corresponding to the largest number of micropores) was observed at 94 K under conditions of fast ice growth while the smallest signal was observed at 120 K under conditions of slow growth. The temperature and pressure dependence of the dangling bond signal during film growth was used to estimate a barrier to diffusion (Edif) for H2O on amorphous ice. We measured an upper limit of Edif = 4.2 (±0.5) kcal mol-1, consistent with a theoretically derived value of Edif = 2.5...
Single-frequency and single-transverse mode Yb-doped CCC fiber MOPA with robust polarization SBS-free 511W output

We demonstrate 511W single-frequency (Δν << 40MHz), single-transverse mode and robust linear polarization output fiber MOPA based on 37µm diameter Yb-doped Chirally-Coupled-Core air-clad fiber.
Characterization of Methanococcus maripaludis sp. nov., a new methanogen isolated from salt marsh sediment

A predominant methanogenic bacterium was isolated from salt-marsh sediment near Pawley's Island, South Carolina. A habitat-simulating medium with H2:CO2 as substrate was used for enrichment and isolation. The methanogen is strictly anaerobic, weakly-motile, non-sporeforming, Gram negative, and a pleomorphic coccoid-rod averaging 1.2 by 1.6 μm. Colonies are circular, translucent, pale yellow, and have a smooth surface and an entire edge. The organism is a mesophile, growing between 18 and 47°C, with an optimum near 38°C. The pH optimum for growth is 6.8–7.2, and only formate or a mixture of H2 plus CO2 serve as substrates. Seawater (20–70% v/v) is required, but it can be replaced by 15 mM, or greater, magnesium. Optimal growth occurs with 110 mM sodium. Growth rate is stimulated by selenium (10 μM) but organic compounds (acetate, vitamins, amino acids) are neither stimulatory nor required. The methanogen grows well in autotrophic medium with a doubling time of about 2h. Cells are fragile, are lysed by aqueous solutions of low osmolality and by detergents, and the lack muramic acid. The cell wall is a single electron dense layer. The DNA base composition is 33 mol % guanine plus cytosine. Antigenic relationship of cells and the 16S ribosomal RNA catalog indicate that the salt marsh methanogen is a unique species of Methanococcus, for which we propose the name Methanococcus maripaludis sp. nov.
Solid structure formation during the liquid/solid phase transition

Abstract This review examines six different mechanisms of forming solid structures by freezing: solidification driven extrusion (SDE), hydrodynamic sputtering, laser-induced periodic surface structures (LIPSS), capillary waves, the Mullins–Sekerka instability, and laser zone texturing. Particular emphasis is placed on how these mechanisms relate to structures formed after melting of surfaces with laser irradiation, even though several of these mechanisms operate also for more conventional melts. The Bally–Dorsey model of SDE explains a mechanism for making spikes of materials that expand upon melting and that scales from the centimeter regime down the nanoscale. Capillary waves are often said to “cause” or be “responsible for” the formation of structures with periodicities Λ ranging anywhere from the wavelength of the incident light to over 10× the wavelength. Here it is shown that while capillary waves formed in conjunction with femtosecond to nanosecond pulsed laser irradiation above the melting threshold support structures with 150 nm ⩽ Λ ⩽ 5 μm, they do not cause the structures to form and some other stimulus is required to select the dominant capillary wave. Capillarity actually inhibits the formation of the smallest structures. Features with larger periodicities can be formed during laser irradiation but they require mass transport that is achieved by, e.g., thermocapillarity or the pressure of the laser ablation plume.
A Technique for Separation of House Dust Mites (Acari: Pyroglyphidae) from Culture Media

House dust mite materials containing D. farinae and their emanations were isolated from laboratory cultures by an ethanol suspension method, and an extract was prepared. The protein nitrogen content of this extract was 250 μg PN/ml. Allergenic potency of the extract was determined by scratch and intracutaneous skin testing. The extract showed good discrimination in patient sensitivity when tested with commercial house dust extracts.
Ethology: Primatological derring-do

Kelly Stewart revels in a graphic biography that follows the human and scientific stories of three iconic primate researchers.
Probing parton thermalization time with charm production.

Preequilibrium parton scattering is shown to make an important contribution to the charm production in relativistic heavy ion collisions. In contrast to the gluon shadowing effect in the initial parton scattering, the enhancement of the final total open charm in the central region due to preequilibrium production could be used as a measure of the thermalization time of the dense partonic system.
Chemotaxis of fibroblasts toward nonapeptide of elastin.

Bovine ligamentum fibroblasts, which produce elastin, migrate towards a positive chemical gradient of human platelet-derived growth factor and of the tropoelastin repeat hexapeptide Val-Gly-Val-Ala-Pro-Gly, as previously shown. They are also responsive to two permutations of a nonapeptide that repeats in tropoelastin, i.e., Ala-Gly-Val-Pro-Gly-Phe-Gly-Val-Gly and Gly-Phe-Gly-Val-Gly-Ala-Gly-Val-Pro. Concentration curves and checkerboard assays prove that the nonapeptides are chemoattractants. The component pentapeptide, Gly-Phe-Gly-Val-Gly, is chemotactic, while the component tetrapeptide Ala-Gly-Val-Pro is not. The hexapeptide competitively suppresses the nonapeptide chemotaxis suggesting the involvement of a common cell receptor. The results support the concept that elastin has multiple cell recognition sites as measured by the chemotactic response and that among the hydrophobic repeating sequences of elastin chemotacticity is selectively and multiply localized.
Photoneutron energy spectra from 24NaBe and 24NaD

Abstract The neutron energy spectra from 9 Be(γ, n) 8 Be and D(γ, n) 1 H photoneutron sources which use 2.75 MeV gamma rays from 24 Na have been measured with a 3 He ionization chamber. A data analysis procedure was developed for dealing with distortions due to severe gamma pileup. The measured spectra are compared to spectra calculated from neutron transport in Be and D 2 O. Peak energies for 24 NaBe and 24 NaD were 957 ± 9 and 245 ± 9 keV, respectively, which may be compared with the calc ulated peak energies of 968 and 265 keV. The average energies for the experimental spectra were 798 ± 71 average energies from the calculated spectra were 796 and 189 keV for 24 NaBe and 24 NaD, respectively.
Taphonomic field experiments and the role of the Shelf and Slope Experimental Taphonomy Initiative

Abstract Fossilization of organism remains is the result of biological, physical, and chemical processes at work in the environment of deposition. The pathways taken by the remains of organisms through death, decay, burial, and diagenesis (known as taphonomic pathways) affect the fossil record of life in important ways, from complete removal and recycling of remains to preservation of hard parts and sometimes to exceptional preservation of soft tissues. Our understanding of taphonomic processes informs our interpretations of the fossil record and helps in the reconstruction of ancient environments. Research into taphonomic pathways in modern environments provides important insight into the fossilization process. In 1993, a group of paleontologists formed the Shelf and Slope Experimental Taphonomy Initiative (SSETI) and began a long-term comparative study of taphofacies and differential decay of taxonomic groups by placing experimental arrays containing bivalves, gastropods, decapod crustaceans, sea urchins, and wood species at multiple marine shelf and slope sites in the Bahamas and Gulf of Mexico. The goal of SSETI is to observe taphonomic processes over a period of decades to better understand taphonomic pathways for these various groups of taxa in a wide variety of depositional environments beyond the shallow near shore region. This special volume brings together eight studies that are the result of the SSETI program. The focus of this contribution is to first review the body of published work concerned with the fossilization process through the experimental manipulation of the remains of organisms in modern marine environments. We also present the methods of the SSETI project and its contributions to our understanding of taphonomic processes in relation to carbonate and wood recycling and preservation.
Fabrication and characterization of thermally actuated micromechanical resonators for airborne particle mass sensing: I. Resonator design and modeling

This paper, the first of two parts, presents a comprehensive electro-thermo-mechanical modeling of thermally actuated in-plane single crystalline silicon MEMS resonators. The resonator structures have been particularly chosen for high-precision measurement of unevenly distributed added masses of airborne particles and high tolerance of air viscous damping. Thermal-piezoresistive transduction has been chosen for the resonators in this work for its robustness against contaminations and airborne particles, as well as fabrication simplicity. However, the operation and electrical equivalent model of such resonators has barely been explored. Analysis and modeling of such resonators is more sophisticated than capacitive or piezoelectric resonators as it includes electrical, thermal and mechanical mechanisms and interactions between them. A combination of finite element analysis, analytical derivations and numerical methods has been utilized in this work to develop the electrical equivalent model of such devices. The modeling strategy developed here can be applied to thermally actuated micromechanical resonators with a variety of other topologies. Fabrication and characterization of the resonators and mass measurement of airborne particles using such resonators is presented in the second part of this paper.
Making institutions: the cultural identity of the Lyric Theatre, Belfast

(2003). Making institutions: the cultural identity of the Lyric Theatre, Belfast. Irish Studies Review: Vol. 11, No. 3, pp. 307-320.
NP-complete scheduling problems

We show that the problem of finding an optimal schedule for a set of jobs is NP-complete even in the following two restricted cases.o(1)All jobs require one time unit. (2)All jobs require one or two time units, and there are only two processor resolving (in the negative a conjecture of R. L. Graham, Proc. SJCC, 1972, pp. 205-218). As a consequence, the general preemptive scheduling problem is also NP-complete. These results are tantamount to showing that the scheduling problems mentioned are intractable.
Thermodynamic Characteristics of pre-mRNA Splice Site Recognition

Here, we reveal that an unusually large enthalpy-entropy compensation underlies recognition of polypyrimidine (Py) splice site signals. Competitive binding to Py tract splice site signals represents a prevalent means for alternative pre-mRNA splicing. The thermodynamic forces driving association of splicing factors with single-stranded (ss) pre-mRNAs represents a gap in the current understanding of splice site selection. We compared Py tract interactions among three splicing factors: (1) U2AF65, an essential pre-mRNA splicing factor that recognizes constitutive 3′ splice site signals; (2) Sex-Lethal, a prototypical alternative splicing factor that antagonizes U2AF65; and (3) TIA-1, an alternative splicing factor that promotes use of specific 5′ splice sites. All three proteins bound polyuridine (U20) sequences with comparable or higher affinity than natural splice site sequences in fluorescence anisotropy assays. Consistent with the ability of Sex-Lethal to outcompete U2AF65 during splice site selection, U2AF65 displayed the lowest and Sex-Lethal the highest affinities for the RNA sites.The enthalpic and entropic contributions were investigated in detail using ITC, initially using the homogeneous U20 site to avoid sequence-dependent complications of the binding isotherms. All three splicing factors exhibited an unusually large enthalpy-entropy compensation underlying U20 binding, with magnitudes ∼10-fold greater than those of typical protein-protein or protein-ligand complexes. Given that full thermodynamic characterizations of protein association with single-stranded RNAs are rare, this raised the question of the source of this unusual thermodynamic signature: Is a large enthalpy-entropy compensation a general characteristic of ssRNA binding, an inherent property of Py tracts, or a signature of sequence-specific ssRNA recognition? These possibilities are clarified by thermodynamic comparison of purine-tract association by these Py tract splicing factors, contrasted with the purine-specific protein PAB.
Influence of Hippotherapy on the Kinematics and Functional Performance of Two Children with Cerebral Palsy

Therapists use hippotherapy to improve postural control in children with neuromotor dysfunction. Understanding the influence of the horse's movement on the child may clarify mechanisms, which influence posture during hippotherapy. This study was conducted in two phases. First measures of the kinemat
Two distinct ATP receptors activate calcium entry and internal calcium release in bovine chromaffin cells.

ATP, an established neurotransmitter, causes elevation of cytosolic Ca 2+ and catecholamine secretion when applied to chromaffin cells in the intact adrenal gland. The ATP-induced rise in Ca 2+ is due both to release from internal stores and to entry across the plasma membrane. The latter source of Ca 2+ causes secretion ; the primary role of Ca 2+ released from internal stores remains undetermined. In this article, we have studied the nucleotide specificity for activating the two types of Ca 2+ increases. The agonist potency order for the increase in fluorescence from fura-2-loaded chromaffin cells due to release of Ca 2+ from internal stores is ATP = UTP > ADP > 2-methylthio-ATP, α,β-methylene ATP, identifying the receptor as a P 2U purinoceptor. The potency order for secretion is 2-methylthio-ATP > ATP > α,β-methylene ATP, ADP, UTP, placing the receptor in the P 2Y subtype. Thus, two distinct receptors are responsible for Ca 2+ release and secretion. Agonists were more effective in the absence of extracellular Mg 2+ , suggesting that ATP uncomplexed with divalent cations binds preferentially to both receptors. The low response of both receptors to ADP distinguishes them from the ATP receptor on these cells that inhibits voltage-dependent Ca 2+ current and secretion.
REPERFUSION FOLLOWING GLOBAL ISCHEMIA: CORONARY FLOW DISTRIBUTION WITH BLOOD VERSUS PERFLUOROCHEMICAL

Unique rheological properties of perfluorochemical emulsions (PF), i.e. smaller particle size and lower viscosity, may improve the distribution of coronary flow following global ischemia. Thus we compared the effects of reperfusion with blood (n=6) and PF(n=6)following 30 minutes of global ischemia, in the isolated perfused (constant flow) rabbit heart. We measured endocardial/epicardial flow ratios (EN/EPI) coronary resistance (RES), and recovery of contractile function (dP/dT), 10 and 120 minutes after global ischemia. All hearts were perfused with blood prior to ischemia. Results are shown in the table. Values are expressed as % of pre-ischemic measurement ± SEM.
A new series of 2-aminomethyltetrahydroquinoline derivatives displaying schistosomicidal activity in rodents and primates.

THE schistosomicidal activity of the mirasan series (I) and of cyclic analogues (II) and (III) in different host species has been reviewed1,2. Members of all three series displayed high activity in mice, but none of these compounds appeared to be active in primates except members of series (III), which displayed some activity in monkeys although they lacked convincing activity in man.
In vivo decomposition of phosphoserine and serine in noncollagenous protein from human dentin

HCl-soluble proteins in human dentin ranging in age from 3 to 45 years exhibit amino acid compositional changes consistent with β-elimination and hydrolysis of phosphoserine as well as dehydration and aldol cleavage of serine. This is the first evidence of nonenzymatic mechanisms forin vivo degradation of hydroxy and substituted hydroxy amino acids in dentin. Decomposition of phosphoseryl residues reduces the calcium-binding capacity of phosphoproteins. Elimination and dehydration reactions can produce variability in molecular weight. The rates of decomposition may be rapid enough to cause the heterogeneity or “maturational” degradation seen in dentin phosphoproteins during mineralization.
Streamflow Characteristics and Changes in Kolyma Basin in Siberia

Abstract This study documents major changes in streamflow hydrology over the Kolyma watershed due to climatic variations and human impacts. Streamflow seasonal cycles over the basin are characteristic of the northern region, with the lowest runoff in April and peak flow in June. Analyses of monthly flows and trends show that reservoir construction and operation have considerably affected streamflow regimes. Comparisons of mean monthly discharge records between pre- and post-1986 dam periods indicate that the mid–lower basin (downstream of the dam) experienced significant increase in low flows and decrease in peak flows after dam construction. For example, mean monthly flows during the post-dam period at the Ust’-Srednekan station (located 1423 km downstream of the dam) has strongly increased by about 205 m3 s−1 (or 522%–3157%) during December–April, and decreased by 133 m3 s−1 (41%) in June. Long-term monthly discharge data reveal an overall increase in streamflow during low flow seasons; the increase is ...
Dartmouth College: The BRS Link

Do you remember when you were a student and you needed five books on some topic for a term paper before tomorrow? After five years of planning and three years of development, the Dartmouth College Library is now making this problem a thing of the past. In fact, at Dartmouth the computer will almost write the paper for you, but that's another story.
Preliminary assessment of the robustness of dynamic inversion based flight control laws

Dynamic-inversion-based flight control laws present an attractive alternative to conventional gain-scheduled designs for high angle-of-attack maneuvering, where nonlinearities dominate the dynamics. Dynamic inversion is easily applied to the aircraft dynamics requiring a knowledge of the nonlinear equations of motion alone, rather than an extensive set of linearizations. However, the robustness properties of the dynamic inversion are questionable especially when considering the uncertainties involved with the aerodynamic database during post-stall flight. This paper presents a simple analysis and some preliminary results of simulations with a perturbed database. It is shown that incorporating integrators into the control loops helps to improve the performance in the presence of these perturbations.
Active surface/subsurface perception for autonomous excavation

Using surface and subsurface sensing, we have developed a perception system for autonomous retrieval of buried objects. The subsurface sensing system uses Ground Penetrating Radar (GPR) to locate buried objects. A 2D laser rangefinder system generates an elevation map, and using this map a robotic arm positions the GPR antenna. This setup allows us to automate the GPR data collection. An image processing algorithm is used to locate the object of interest in the GPR data. After it is located, we use sense and dig cycle to retrieve the object.
Transnational environmental problems — The United States, Canada, Mexico

The paper examines the problems associated with transboundary environmental pollution. While briefly recording the efforts of international organizations in this area, the main content of the paper is concerned with an analysis of problems arising between the United States and Mexico, and between the United States and Canada. The paper also discusses new organizational forms that have been developed to bring transboundary issues to a higher policy-making level.
National analysis of in-hospital resource utilization in choledocholithiasis management using propensity scores.

Background Two treatment options exist for choledocholithiasis (CDL): endoscopic retrograde cholangiopancreatography (ERCP) and common bile duct exploration (CBDE). Resource utilization measured by total in-hospital charges (THC) and length of stay (LOS) was compared using the propensity score (PS). In this study, PS was the probability that a patient received CBDE based on comorbidities and demographics. The power of this method lies in balancing groups on variables by PS, resulting in 90% bias reduction and improved inferential validity compared to traditional analytic techniques.
Soluble Sunscreens Fully Protect E. coli from Disinfection by Electrohydraulic Discharges

We show that the ultraviolet radiation emitted, rather than the thermal/pressure shocks or the chemical species that are generated in these events, is the lethal agent that inactivates Escherichia coli colonies exposed to electrohydraulic discharges, EHD. Disinfection is completely suppressed in the presence of <100 mg L^(-1) of 2,2‘-dihydroxy-4,4‘-dimethoxybenzophenone-5,5‘-disulfonic acid, BP9, a commercial water-soluble sunscreen. Viable bacteria decay by logit kinetics with the number of EHD. The fact that the slopes of the logit plots depend inversely on BP9 concentration, and vanish above ∼ 30 mg BP9 L^(-1), is direct evidence that E. coli is exclusively sterilized by UV radiation in these experiments. Present LD_(50) photon doses are about 10^3 times larger than those required from low-power germicidal lamps, indicating that high-intensity radiation is able to further promote into inactive channels the lower excited state(s) of nucleic acids responsible for DNA damage. The present study confirms the existence of a significant trade-off between photon efficiency and radiative power in bacterial disinfection by UV light.
Molecular dynamics simulation studies of cytochrome b5 from outer mitochondrial and microsomal membrane.

Two forms of cytochrome b5 have been identified, associated with the outer membrane of liver mitochondria (OM cyt b5) and with the membrane of the endoplasmic reticulum (microsomal, Mc cyt b5). These proteins have very similar structures, but differ significantly in physical properties, with the OM cyt b5 exhibiting a more negative reduction potential, higher stability, and stronger interactions with the heme. We perform molecular dynamics simulations to probe the structures and fluctuations of the two proteins in solution, to help explain the observed physical differences. We find that the structures of the two proteins, highly similar in the crystal, differ in position of a surface loop involving residues 49–51 in solution. Hydrophobic residues Ala-18, Ile-32, Leu-36, and Leu-47 tend to cluster together on the surface of rat OM cyt b5, blocking water access to the protein interior. In bovine Mc cyt b5, two of these positions, Ser-18 and Arg-47, are occupied by hydrophilic residues. This leads to breaking the hydrophobic cluster and allowing the protein to occupy a more open conformation. A measure of this structural transition is the opening of a cleft on the protein surface, which is 5 A wider in the OM cyt b5 simulation compared to the Mc form. The OM protein also appears to have a more compact hydrophobic core in its β-sheet region. These effects may be used to explain observed stability differences between the two proteins. © 2003 Wiley Periodicals, Inc. Biopolymers 69: 260–269, 2003
Volleyball and Other Analogies A Response to Englert

Englert and her colleagues have contributed much to our knowledge about effective writing instruction. They have demonstrated that interventions that make explicit the writing process and text structures are successful with students with learning disabilities as well as those without. Englert attributes this success to the holistic, social, and interactive nature of the instruction. However, one must keep in mind that CSIW was a package approach that included other validated instructional components. CSIW teachers presented conceptual models, used examples and nonexamples to illustrate text structure concepts, modeled thinking overtly while demonstrating the process, provided guided practice by prompting the process through dialogue and think-sheets, faded prompts as students took over more of the responsibility for the process, and taught for generalization by addressing more than one text structure and promoting student talk about the process. As Englert reported, most teachers seldom do these things, even when they claim to teach the writing process. Englert allows for the possibility that all students with learning disabilities may not be ready for cognitive strategy instruction as it is described in her article, and professionals must acknowledge that different techniques may be more effective for students of different ages and abilities. Swanson (1990) emphasized that there must be a match between strategy and learner characteristics and that strategies must be considered in relation to a student's knowledge and capacity. Strategic teaching requires that the teacher have a repertoire of approaches along a continuum that encompasses coaching students to use their own mental resources at one end and basic skill instruction at the other.(ABSTRACT TRUNCATED AT 250 WORDS)
Percutaneous Abscess Drainage in Gynecologic Cancer Patients

Percutaneous abscess drainage (PAD) is regarded as an alternative treatment for the care of the gynecologic cancer patient with a pelvic infection. Four female patients with infected pelvic malignancies were evaluated and treated with PAD at Thomas Jefferson University Hospital over a 4-year period. Abscesses in three of the four patients were drained successfully and the catheters were ultimately removed. Successful drainage was defined as a good clinical response and avoidance of surgical debridement. For the patient with an infected pelvic malignancy, PAD offers an alternative to surgery without associated morbidity. Our experience indicates PAD is associated with expedient clinical recovery and preservation of quality of life for most patients.
On the mechanism of strand assimilation by the herpes simplex virus type‐1 single‐strand DNA‐binding protein (ICP8)

ICP8, the herpes simplex virus type-1 encoded single-strand DNA (ssDNA)-binding protein, promotes the assimilation of a single-stranded DNA molecule into a homologous duplex plasmid resulting in the formation of a displacement loop. Here we examine the mechanism of this process. In contrast to the RecA-type recombinases that catalyze strand invasion via an active search for homology, ICP8 acts by a salt-dependent strand annealing mechanism. The active species in this reaction is a ssDNA:ICP8 nucleoprotein filament. There appears to be no requirement for ICP8 to interact with the acceptor DNA. At higher concentrations, ICP8 promotes the reverse reaction, presumably owing to its helix destabilizing activity. ICP8-mediated strand assimilation imparts single-stranded character onto the acceptor DNA, consistent with the formation of a displacement loop. These data suggest that the recombination activity of ICP8 is similar to the mechanism of eukaryotic Rad52.
On the Mechanism of Contact Coiling of Tendrils

Although Charles Darwin is best known for his discovery of biological evolution, he was the eclectic natural scientist par excellence, and in the tradition of the classical naturalists such as Aristotle and Pliny the Elder, considered all the world of nature within the domain of his interests. Among these, his observations of plants, recorded in several books [e.g., (10–13)], papers and letters (14), apparently gave him special joy, because he writes in his autobiography: “it has always pleased me to exalt plants in the scale of organized beings”; (8).
Justifying small-n research in scientifically amazing settings: challenging the notion that only "big-n" studies are worthwhile.

if you have ever competed for external research support, you know the drill. Every grant starts with some fantastic ideas that are honed, filtered, and shaped into a grant proposal. Primary aims lead to hypothesis statements, definitions of primary outcomes, and a statistical analysis section. At
Reconceptualizing the Role of Security User

Abstract The Internet is not the only critical infrastructure that relies on the participation of unorganized and technically inexpert end users. Transportation, health, waste management, and disaster preparedness are other areas where cooperation between unorganized citizens who lack experience with the domain has increased resiliency, reduced social costs, and helped meet shared goals. Theories of community-based production and management of the commons explain this type of cooperation, both offline and online. This essay examines these two complementary approaches to organizing the cybercitizen for cybersecurity. Cybersecurity discourse has reasonably focused on centralized parties and network operators. From domain name registrars to network service providers, solutions are sought through incentives, regulation, and even law enforcement. However great the ability of these centralized entities to implement change, the end user plays a crucial role. The Internet must remain open to enable innovation and...
Fine structure of the genital papillae of Hormosianoetus mallotae (Fashing) (Astigmata: Histiostomatidae), an obligatory inhabitant of water-filled treeholes

Abstract Scanning and transmission electron microscopy (SEM and TEM) reveal that the genital papillae (= ring organs) of Hormosianoetus mallotae (Fashing) consist of a central disk of modified cuticle surrounded by a thickened ring of normal cuticle. Beneath the disk is an electron-lucent chamber separating it from modified cells below that contain numerous mitochondria in close association with plasma membrane plications, a fine-structural characteristic of cells with an active transport function. Hormosianoetus mallotae is an obligate inhabitant of water-filled treeholes and a completely aquatic species. Evidence points toward osmoregulation and/or ion regulation as the probable function of genital papillae in freshwater mites, and, based on fine structure, this is their probable function in Hormosianoetus mallotae as well. To date, the genital papillae of only one other species of histiostomatid, Histiostoma feroniarum (Dufour), have been investigated. Although both species share many fine-structural c...
A strong species–area relationship for eukaryotic soil microbes: island size matters for ectomycorrhizal fungi

While the effects of habitat size and isolation have been successfully studied for macroorganisms, there is currently debate about their relative importance in explaining patterns of microbial species richness. In this study, we examine the species richness of a dominant group of eukaryotic soil microbes, ectomycorrhizal fungi, on tree islands of constant age and host composition that range in size from 10 000 m 2 . Our results show that ectomycorrhizal species richness is significantly reduced on smaller and more isolated tree islands, and the species‐area slope that we observe (0.20‐0.23) is similar to average slopes reported for macro-organisms. Additionally, species occurrence patterns across tree islands and investment trends in fungal fruit bodies suggest that a trade-off between competition and dispersal could play an important role in structuring ectomycorrhizal assemblages.
Interkingdom signaling by structurally related cyanobacterial and algal secondary metabolites

Several groups of structurally-related compounds, comprised of either five or six-membered ring structures with attached lipophilic carbon chains and in some cases possessing halogen atoms, have been isolated from various marine algae and filamentous cyanobacteria. The related compounds considered in the present work include the coibacins, laurenciones, honaucins, malyngamides and the tumonoic acids. Members of all of these compound families were assayed and found to inhibit the production of nitric oxide in lipopolysaccharides-stimulated macrophages, indicating their anti-inflammatory potential. In addition, several of these same marine natural products were found to inhibit quorum sensing mediated phenotypes in Vibrio harveyi BB120 and/or Escherichia coli JB525. The mechanism and evolutionary significance for inhibition of these cellular processes in prokaryotic and eukaryotic systems are speculated on and discussed.
Mortgaging Security for Economic Gain: U.S. Arms Policy in an Insecure World

Similar to other consumer sectors of the global economy, the transfer of advanced conventional weapons and military technologies has entered the globalization process, a process that has qualitatively and quantitatively altered the composition and structure of U.S. national security policymaking. By injecting the decisionmaking process governing arms transfers into the global market place, U.S. policy makers must now reconcile maintaining economic competitiveness within the global system without jeopardizing U.S. national security interests. By subordinating national security interests to global economic imperatives, U.S. decisionmakers are at risk of mortgaging the political, societal, and security welfare of its citizenry for profit.
Packet Forwarding Using Pipelined Multibit Tries

We propose a heuristic for the construction of variablestride multibit tries. These multibit tries are suitable for packet forwarding using a pipelined architecture. The variable-stride tries constructed by our heuristic require upto 1/32 of the per-stage memory required by optimal pipelined fixed-stride tries. We also develop a tree packing heuristic, which dramatically reduces the per-stage memory required by fixed- and variable-stride multibit tries constructed for pipelined architectures. On publicly available router databases, our tree packing heuristic reduces the maximum per-stage memory required by optimal pipelined fixed-stride tries
Collision avoidance and resolution multiple access with transmission groups

The CARMA-NTG protocol is presented and analyzed. CARMA-NTG dynamically divides the channel into cycles of variable length; each cycle consists of a contention period and a group-transmission period. During the contention period, a station with one or more packets to send competes for the right to be added to the group of stations allowed to transmit data without collisions; this is done using a collision resolution splitting algorithm based on a request-to-send/clear-to-send (RTS/CTS) message exchange with non-persistent carrier sensing. CARMA-NTG ensures that one station is added to the group transmission period if one or more stations send requests to be added in the previous contention period. The group-transmission period is a variable-length train of packets, which are transmitted by stations that have been added to the group by successfully completing an RTS/CTS message exchange in previous contention periods. As long as a station maintains its position in the group, it is able to transmit data packets without collision, An upper bound is derived for the average costs of obtaining the first success in the splitting algorithm. This bound is then applied to the computation of the average channel utilization in a fully connected network with a large number of stations. These results indicate that collision resolution is a powerful mechanism in combination with floor acquisition and group allocation multiple access.
Aurora B-dependent Regulation of Class IIa Histone Deacetylases by Mitotic Nuclear Localization Signal Phosphorylation

Class IIa histone deacetylases (HDACs 4/5/7/9) are transcriptional regulators with critical roles in cardiac disease and cancer. HDAC inhibitors are promising anticancer agents, and although they are known to disrupt mitotic progression, the underlying mechanisms of mitotic regulation by HDACs are not fully understood. Here we provide the first identification of histone deacetylases as substrates of Aurora B kinase (AurB). Our study identifies class IIa HDACs as a novel family of AurB targets and provides the first evidence that HDACs are temporally and spatially regulated by phosphorylation during the cell cycle. We define the precise site of AurB-mediated phosphorylation as a conserved serine within the nuclear localization signals of HDAC4, HDAC5, and HDAC9 at Ser265, Ser278, and Ser242, respectively. We establish that AurB interacts with these HDACs in vivo, and that this association increases upon disruption of 14-3-3 binding. We observe colocalization of endogenous, phosphorylated HDACs with AurB at the mitotic midzone in late anaphase and the midbody during cytokinesis, complemented by a reduction in HDAC interactions with components of the nuclear corepressor complex. We propose that AurB-dependent phosphorylation of HDACs induces sequestration within a phosphorylation gradient at the midzone, maintaining separation from re-forming nuclei and contributing to transcriptional control.
Mental health symptoms and patient-reported diabetes symptom burden: implications for medication regimen changes

Aims. To examine the relative contribution of glycaemic control (HbA1C) and depressive symptoms on diabetes-related symptom burden (hypoglycaemia and hyperglycaemia) in order to guide medication modification.
Role for the Ssu72 C-terminal domain phosphatase in RNA polymerase II transcription elongation.

The RNA polymerase II (RNAP II) transcription cycle is accompanied by changes in the phosphorylation status of the C-terminal domain (CTD), a reiterated heptapeptide sequence (Y1S2P3T4S5P6S7) present at the C terminus of the largest RNAP II subunit. One of the enzymes involved in this process is Ssu72, a CTD phosphatase with specificity for serine-5-P. Here we report that the ssu72-2-encoded Ssu72-R129A protein is catalytically impaired in vitro and that the ssu72-2 mutant accumulates the serine-5-P form of RNAP II in vivo. An in vitro transcription system derived from the ssu72-2 mutant exhibits impaired elongation efficiency. Mutations in RPB1 and RPB2, the genes encoding the two largest subunits of RNAP II, were identified as suppressors of ssu72-2. The rpb1-1001 suppressor encodes an R1281A replacement, whereas rpb2-1001 encodes an R983G replacement. This information led us to identify the previously defined rpb2-4 and rpb2-10 alleles, which encode catalytically slow forms of RNAP II, as additional suppressors of ssu72-2. Furthermore, deletion of SPT4, which encodes a subunit of the Spt4-Spt5 early elongation complex, also suppresses ssu72-2, whereas the spt5-242 allele is suppressed by rpb2-1001. These results define Ssu72 as a transcription elongation factor. We propose a model in which Ssu72 catalyzes serine-5-P dephosphorylation subsequent to addition of the 7-methylguanosine cap on pre-mRNA in a manner that facilitates the RNAP II transition into the elongation stage of the transcription cycle.
r-Kernel: An operating system foundation for highly reliable networked embedded systems

In this paper, we present r-kernel, an operating system kernel foundation specifically designed to improve software reliability in networked embedded systems. The key novelty of r-kernel lies in that it exploits the time dimension of software execution to improve robustness. Specifically, r-kernel keeps track of the execution of applications through checkpoints. If one application has been determined to have failed, r-kernel performs rollback operations to restore its state to one of those checkpoints created earlier. For the second round of operation, r-kernel provides a safe mode environment to avoid triggering the same bugs. Finally, if the whole system has crashed, r-kernel relies on watchdog timers to reset the node, and develops a technique called past-run trace reconstruction to locate and report the thread that had caused the system failure. We have implemented r-kernel based on the LiteOS operating system kernel running on the popular MicaZ platform. We demonstrate that it achieves the desired goals above with acceptable overhead.
The diurnal salinity cycle in the tropics

Observations from 35 tropical moorings are used to characterize the diurnal cycle in salinity at 1 m depth. The amplitude of diurnal salinity anomalies is up to 0.01 psu and more typically ∼0.005 psu. Diurnal variations in precipitation and vertical entrainment appear to be the dominant drivers of diurnal salinity variability, with evaporation also contributing. Areas where these processes are strong are expected to have relatively strong salinity cycles: the eastern Atlantic and Pacific equatorial regions, the southwestern Bay of Bengal, the Amazon outflow region, and the Indo-Pacific warm pool. We hypothesize that salinity anomalies resulting from precipitation and evaporation are initially trapped very near the surface and may not be observed at the 1 m instrument depths until they are mixed downward. As a result, the pattern of diurnal salinity variations is not only dependent on the strength of the forcing terms, but also on the phasing of winds and convective overturning. A comparison of mixed-layer depth computed with hourly and with daily averaged salinity reveals that diurnal salinity variability can have a significant effect on upper ocean stratification, suggesting that representing diurnal salinity variability could potentially improve air-sea interaction in climate models. Comparisons between salinity observations from moorings and from the Aquarius satellite (level 2 version 3.0 data) reveal that the typical difference between ascending-node and descending-node Aquarius salinity is an order of magnitude greater than the observed diurnal salinity anomalies at 1 m depth.
The TonB Dimeric Crystal Structures Do Not Exist In Vivo

The TonB system energizes transport of nutrients across the outer membrane of Escherichia coli using cytoplasmic membrane proton motive force (PMF) for energy. Integral cytoplasmic membrane proteins ExbB and ExbD appear to harvest PMF and transduce it to TonB. The carboxy terminus of TonB then physically interacts with outer membrane transporters to allow translocation of ligands into the periplasmic space. The structure of the TonB carboxy terminus (residues ~150 to 239) has been solved several times with similar results. Our previous results hinted that in vitro structures might not mimic the dimeric conformations that characterize TonB in vivo. To test structural predictions and to identify irreplaceable residues, the entire carboxy terminus of TonB was scanned with Cys substitutions. TonB I232C and N233C, predicted to efficiently form disulfide- linked dimers in the crystal structures, did not do so. In contrast, Cys substitutions positioned at large distances from one an- other in the crystal structures efficiently formed dimers. Cys scanning identified seven functionally important residues. How- ever, no single residue was irreplaceable. The phenotypes conferred by changes of the seven residues depended on both the specific assay used and the residue substituted. All seven residues were synergistic with one another. The buried nature of the residues in the structures was also inconsistent with these properties. Taken together, these results indicate that the solved dimeric crystal structures of TonB do not exist. The most likely explanation for the aberrant structures is that they were obtained in the absence of the TonB transmembrane domain, ExbB, ExbD, and/or the PMF. IMPORTANCE The TonB system of Gram-negative bacteria is an attractive target for development of novel antibiotics because of its importance in iron acquisition and virulence. Logically, therefore, the structure of TonB must be accurately understood. TonB functions as a dimer in vivo, and two different but similar crystal structures of the dimeric carboxy-terminal ~90 amino acids gave rise to mechanistic models. Here we demonstrate that the crystal structures, and therefore the models based on them, are not biologically relevant. The idiosyncratic phenotypes conferred by substitutions at the only seven functionally important residues in the carboxy terminus suggest that similar to interaction of cytochromes P450 with numerous substrates, these resi- dues allow TonB to differentially interact with different outer membrane transporters. Taken together, data suggest that TonB is maintained poised between order and disorder by ExbB, ExbD, and the proton motive force (PMF) before energy transduction to the outer membrane transporters.
Biomass-Derived Hydrogen from a Thermally Ballasted Gasifier

The goal of this project is to develop an indirectly heated gasification system that converts switchgrass into hydrogen-rich gas suitable for powering fuel cells. The project includes investigations of the indirectly-heated gasifier, development of particulate removal equipment, evaluation of catalytic methods for upgrading producer gas, development of contaminant measurement and control techniques, modeling of the thermal performance of the ballasted gasifier, and estimation of the cost of hydrogen from the proposed gasification system. Specific technologies investigated include a thermally ballasted gasifier, a moving bed granular filter, and catalytic reactors for steam reforming and water-gas shift reaction. The approach to this project was to employ a pilot-scale (5 ton per day) gasifier to evaluate the thermally ballasted gasifier as a means for producing hydrogen from switchgrass. A slipstream from the gasifier was used to evaluate gas cleaning and upgrading options. Other tests were conducted with laboratory-scale equipment using simulated producer gas. The ballasted gasifier operated in conjunction with a steam reformer and two-stage water-gas shift reactor produced gas streams containing 54.5 vol-% H2. If purge gas to the feeder system could be substantially eliminated, hydrogen concentration would reach 61 vol-%, which closely approaches the theoretical maximum of 66 vol-%. Tests with more » a combined catalyst/sorbent system demonstrated that steam reforming and water-gas shift reaction could be substantially performed in a single reactor and achieve hydrogen concentrations exceeding 90 vol-%. Cold flow trials with a laboratory-scale moving bed granular filter achieved particle removal efficiencies exceeding 99%. Two metal-based sorbents were tested for their ability to remove H2S from biomass-derived producer gas. The ZnO sorbent, tested at 450° C, was effective in reducing H2S from 200 ppm to less than 2 ppm (>99% reduction) while tests with the MnO sorbent were inconclusive. A computer model was developed that successfully predicted the thermal performance of the ballasted gasifier. An economic comparison of an air-blown gasification plant and a ballasted gasifier plant found that operating costs for ballasted gasification plant are about 31% higher than for the air blown gasifier plant. Hydrogen from the ballasted gasification plant and air blown gasification plant are projected to be $2.43/kg and $1.85/kg, respectively. This is lower than U.S. DOE’s 2010 target price of $2.90/kg and comparable to U.S. DOE’s 2015 target price of $2.00/kg. « less