cssi/SciSciGPT-SciSciNet huggingface dataset:
Modulated molecular beam growth of mixed As/Sb layers for mid-infrared lasers

Short period superlattices of the ternary InGaAs/InGaSb alloys are grown by molecular beam epitaxy with the intent of approximating a quaternary InGaAsSb alloy. This technique where a quaternary semiconductor alloy is replaced by building short period superlattices using its ternary constituents is referred to as 'digital alloying.' Three sets of 2 micrometer In0.1Ga0.9AsySb1-y bulk alloys are grown; the first set was grown conventionally with varying growth temperature, while the other two sets were grown digitally. The first set of digital alloys lattice matched to GaSb is grown at various substrate temperatures, the second set was grown at one constant growth temperature but with various superlattice periodicities. Using high-resolution x-ray diffraction and room temperature photoluminescence, the structural and optical properties of the bulk In0.1Ga0.9AsySb1-y alloys were investigated. It is observed that the digital alloys are less sensitive to changes in the growth temperature by a factor of approximately 3, and the maximum periodicity a digital alloy can be grown before the onset of relaxation is approximately 9 ML. An optically pumped approximately 2 micrometer laser structure with InGaAsSb quantum wells and AlGaAsSb barriers both grown using the digital alloy technique was characterized. Room temperature operation, a low threshold current density of 104 W/cm2 (at 80 K with 808 nm pump), and a high characteristic temperature (TO) of 104 K show the feasibility of applying digital alloying techniques to mid-infrared optical devices.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Ultrafast dynamic holography in nanocrystal solids

We report efficient dynamic gratings in close-packed solids of CdSe nanocrystals. These gratings are formed on the subpicosecond time scale and have diffraction efficiencies up to 0.5% for film thicknesses of ∼0.5 μm. Nanocrystal solids combine the best features of inorganic semiconductors (large resonant nonlinearities and high photostability) and organic semiconducting polymers (chemical flexibility and tunability of optical properties by simple synthetic means). Additionally, nanocrystal solids allow precise control over the spectral position of the nonlinear optical response by simply varying the size of the nanocrystals used in fabricating the solid (quantum confinement effect).
Heat stress induces the synthesis of a new form of ribulose-1,5-bisphosphate carboxylase/oxygenase activase in cotton leaves.

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) activase mRNA and protein synthesis were measured in the leaves of cotton (Gossypium hirsutum L.) plants under control (28 °C) or heat-stress (41 °C) conditions. A decline in activase transcript abundance occurred rapidly during the photoperiod and was unaffected by heat stress. In response to high temperature, de novo protein synthesis rapidly shifted from mainly expression of Rubisco large and small subunits to the major heat-shock proteins, while de novo synthesis of the constitutively expressed 47- and 43-kDa activase polypeptides was not appreciably altered. However, heat stress induced the synthesis of a 46-kDa polypeptide that immunoprecipitated with antibodies monospecific to activase. Expression of the 46-kDa polypeptide ceased within 1 h of the return of heat-stressed plants to control conditions. Activase precursors of 55 and 51 kDa were detected among the in vitro translation products of RNA from control and heat-stressed plants. In addition, a 53-kDa polypeptide that also immunoprecipitated with anti-activase IgG was among the in vitro translation products of RNA from heat-stressed plants. This putative activase precursor did not occur among the in vitro translation products of RNA from plants that had recovered from heat stress. The levels of the constitutive 47- and 43-kDa activase polypeptides were similar in control and heat-stressed plants, based on immunoblotting with antibodies to activase. However, a 46-kDa cross-reacting polypeptide was also present in heat-stressed plants and constituted about 5% of the total activase after 48 h at high temperature. The identity of the heat-induced 46-kDa polypeptide as activase was confirmed by protein sequencing, which showed that its N-terminal sequence was identical to that of the constitutive 47-kDa activase polypeptide. The presence of multiple isoforms for both the 47- and 43-kDa activase polypeptides on immunoblots of two-dimensional gels and the complex banding pattern on Southern blots together suggest the existence of more than one activase gene and the possibility that the synthesis of the heat-induced activase polypeptide may be regulated transcriptionally. Induction of a new form of activase may constitute a mechanism of photosynthetic acclimation to heat stress in cotton.
Caspase-mediated activation of Caenorhabditis elegans CED-8 promotes apoptosis and phosphatidylserine externalization.

As they die, apoptotic cells present phosphatidylserine on the outer leaflet of the plasma membrane, which serves as an ‘eat-me’ signal for nearby phagocytes. Chen et al. identify the caspase substrate CED-8 as a key regulator of phosphatidylserine externalization during apoptosis in C. elegans.
Partial Fertility of Artificial Hybrids between Asiatic and American Cockleburs ( Xanthium strumarium L.)

MORPHOLOGICALLY diverse populations of cockleburs (Xanthium strumarium L.) occur sympatrically in Europe and Asia and maintain their identity despite reports of gene exchange within the taxon1–4. As early as 1908, Bitter5 produced hybrids between various cockleburs in Europe and although unable to hybridise X. spinosum L. with X. strumarium, he produced intermediates between the putative indigenous plants of Europe (X. strumarium6, 7 or the strumarium morphological complex1) and other morphological types. To understand the role of hybridisation in the worldwide adaptation of Xanthium, plants of the strumarium morphological complex (X. inaequilaterum DC7, Hong Kong; X. indicum Konig7, India) were crossed experimentally with plants in the American morphological complexes1, italicum, chinense, pennsylvanicum, cavanillesii and oviforme. The fertility of these hybrids was compared with that of inter-Asiatic and inter-American F1 plants.
Carotid Baroreceptor Activation for the Treatment of Resistant Hypertension and Heart Failure

Carotid baroreceptors play an important role in blood pressure regulation through modification of sympathetic nervous activity. Conditions associated with increased sympathetic activity, such as resistant hypertension and heart failure, represent potential targets for carotid baroreceptor activation. Recent technological advances made available a small device, like a pacemaker, that constantly activates carotid baroreceptors. Primary experimental and clinical data obtained from use of this device point toward significant blood pressure reduction in patients with resistant hypertension, as well as beneficial effects on cardiac structure and function. A large feasibility trial revealed promising results; however, the first randomized study in patients with resistant hypertension raised several concerns regarding the efficacy and safety of baroreceptor activation with the device. This review critically evaluates available data obtained with carotid baroreceptor activation, emphasizing data acquired during the past year, and discusses the advantages and disadvantages as well as the future prospects of this intervention.
Supply chain structure and demand risk

V. Agrawal and S. Seshadri (2000) [Risk intermediation in supply chains. IIE Transactions, 32, 819-831] considered a problem in which a single risk neutral distributor supplies a short-lifecycle, long-leadtime product to several retailers that are identical except in their attitudes towards risk. They proved that the distributor should not offer the same terms to every retailer but instead offer less risky (from the demand risk perspective) contracts to more risk averse retailers. They did not prove the optimality of their menu. In this paper we reconstruct their results when the number of retailers is infinite and their coefficient of risk aversion is drawn from a continuous distribution. We use optimal control theory to solve this problem. We show that this distribution uniquely determines the channel structure. Moreover, the optimal contract menu not only has the same structure as in Agrawal and Seshadri but is also optimal among nearly all contracts. The implications of these findings for channel design are discussed.
Compton Scatter in Germanium and Its Effect on Imaging with Gamma-Ray Position-Sensitive Detectors

The spatial spread due to Compton scatter in Ge was measured to study the reduction in image contrast and signal-to-noise ratio (S/N) resulting from erroneous readout in Ge position-sensitive detectors. The step response revealing this spread was obtained by scanning with a 122 keV ?-ray beam across a boundary of two sectors of a slotted coaxial Ge(Li) detector that is 40 mm diameter by 22 mm long. The derived line-spread function at 140 keV (99mTc) exhibits much shorter but thicker tails than those due to scatter in tissue as observed with a NaI detector through 5.5 cm of scattering material. Convolutions of rectangular profiles of voids with the Ge(Li) line-spread function show marked deterioration in contrast for voids less than 10 mm across, which in turn results in even greater deterioration of the S/N. As a result, the contrast for voids in Ge images is only 20-30% higher than that in NaI and the S/N is only comparable for equal detector areas. The degradation in image contrast due to scatter in Ge detectors can be greatly reduced by either using thin detectors (~5 mm), where scatter virtually does not exist, or by using thicker detectors and rejecting scatter electronically. To reduce the effects of scatter on the S/N as well as on contrast, the erroneous position readouts must actually be corrected.
Affective Responses to an Aerobic Dance Class: The Impact of Perceived Performance.

Abstract The current study tests the mastery hypothesis as an explanation for the affective benefits of acute exercise. Participants were 204 undergraduate women who were participating in self-selected aerobic dance classes. Following the class, participants were asked to rate their exercise performance on a 5-point, Likert-type scale. Affect questionnaires were completed prior to and at 5 and 20 min following the aerobic dance class. Results indicated an overall improvement in affect following exercise. Negative valenced subscales were unaffected by performance ratings. Both groups showed similar reductions in these states. There was, however, a significant Group × Time interaction for the positive valenced subscales. High-performance participants reported greater increase in these variables throughout recovery than did low-performance participants. These data support the mastery hypothesis as an explanation for the exercise-induced change in positive affective states.
Charge and spin ordering in the mixed-valence compound LuFe 2 O 4

Landau theory and symmetry considerations lead us to propose an explanation for several seemingly paradoxical behaviors of charge ordering (CO) and spin ordering (SO) in the mixed valence compound ${\text{LuFe}}_{2}{\text{O}}_{4}$. Both SO and CO are highly frustrated. We analyze a lattice gas model of CO within mean-field theory and determine the magnitude of several of the phenomenological interactions. We show that the assumption of a continuous phase transitions at which CO or SO develops implies that both CO and SO are incommensurate. To explain how ferroelectric fluctuations in the charge-disordered phase can be consistent with an antiferroelectric-ordered phase, we invoke an electron-phonon interaction in which a low-energy (20 meV) zone-center transverse phonon plays a key role. The energies of all the zone center phonons are calculated from first principles. We give a Landau analysis which explains SO and we discuss a model of interactions which stabilizes the SO state, if it is assumed commensurate. However, we suggest a high-resolution experimental determination to see whether this phase is really commensurate, as believed up to now. The applicability of representation analysis is discussed. A tentative explanation for the sensitivity of the CO state to an applied magnetic field in field-cooled experiments is given.
Serological and biochemical characterization of rat (RT1) class II molecules with restricted mouse anti-Ia sera.

Murine anti-Ia sera were tested for their reactivity with rat peripheral lymphocytes. Extensive cross-reactions were observed in a complement-dependent cytotoxicity assay. In the majority of strain combinations, these reactions were specific for B cells. We demonstrated by absorption analyses that (1) the reaction was specific, (2) B cells from all rat strains reacted with anti-I-Ek serum, and (3) the anti-I-A sera defined five new specificities. These antisera can also immunoprecipitate class II (Ia-like) molecules from radiolabeled, detergent-solubilized cell extracts. The rat equivalents of molecules encoded in the I-A and I-E subregions in mice can be isolated from all rat strains studied. The α and β subunits of the rat class II molecules were polymorphic when analyzed by sodium dodecyl sulfate (SIDS) polyacrylamide electrophoresis. This observation allows the characterization of rat alloantisera or monoclonals of unknown specificity by comparing them to the defined reactivity of the mouse anti-Ia sera.
Utilizing a Microcomputer Based Flight Simulation in Teaching Human Factors in Aviation

This paper describes the use of Microsoft's “Flight Simulator” and “Flight Simulator: Aircraft and Scenery Designer” in teaching human factors in aviation to psychology and engineering students. The student's role commenced as that of a participant-observer and concluded as that of a scientist-practitioner. Flight Simulator was used to familiarize the student with aerodynamic principles, the relationship between aircraft controls and displays and flight dynamics. Both the syllabus incorporating the flight simulation and the capabilities of the simulation are described. The authors examined the capabilities of the simulations and feel that they provide an excellent return for a comparatively small investment. Students felt that the ability to use a simulator greatly enhanced the course. The simulations have potential applications which remain to be tapped. As a teaching aid, it is rated “best buy”.
Capacity of old versus young male rats to release thyrotropin (TSH), thyroxine (T4) and triiodothyronine (T3) in response to different stimuli

Abstract Serum TSH, T. and T, were measured by radioimmunoassay (RIA) in 20–24 month old and 6–8 month old Long-Evans male rats during basal conditions, and upon exposure to cold temperature (4°C), injection of ovine TSH, thyroidectomy, and T4 or T3 treatment. Basal serum TSH values in the old and young rats were similar, but serum T4 and T3 levels in the old rats were significantly lower than in the young rats. No differences were observed in TSH release between old and young rats in response to cold temperature, but old rats showed no rise in serum T4. TSH administration produced a significantly smaller increase in serum T4 in old rats, but similar increases in serum T3 in old and young rats. No differences were observed between old and young rats in the rise of serum TSH after thyroidectomy, or in the fall of serum TSH after T4 or T3 administration. These results are believed to indicate that the primary cause for reduced thyroid function in old rats lies in the thyroid gland itself.
Designing robust microarchitectures

A fault-tolerant approach to microprocessor design, developed at the University of Michigan, is presented. Our approach is based on the use of in-situ checker components that validate the functional and electrical characteristics of complex microprocessor designs. Two design techniques are highlighted: a low-cost double-sampling latch design capable of eliminating power-hungry voltage margins, and a formally verifiable checker co-processor that validates all computation produced by a complex microprocessor core. By adopting a "better than worst-case" approach to system design, it is possible to address reliability and uncertainty concerns that arise during design, manufacturing and system operation.
Starting with Two Matrices

Imagine that you have never seen matrices. On the principle that examples are amazingly powerful, we study two matrices A and C . The reader is requested to be exceptionally patient, suspending all prior experience—and suspending also any hunger for precision and proof. Please allow a partial understanding to be established first. The first sections of this paper represent an imaginary lecture, very near the beginning of a linear algebra course. That lecture shows by example where the course is going. The key ideas of linear algebra (and the key words) come very early, to point the way. My own course now includes this lecture, and Notes 1-6 below are addressed to teachers.
Corrosion-resistant high-reflectance Mg/SiC multilayer coatings for solar physics in the 25-80 nm wavelength region

The corrosion mechanisms in Mg/SiC multilayers have been elucidated and corrosion-resistant Mg/SiC multilayer coatings have been demonstrated using spontaneously intermixed Al-Mg corrosion barrier layers. The corrosion-resistant Mg/SiC multilayers can achieve high reflectance simultaneously in up to three narrow wavelength bands within the 25-80 nm wavelength region, making them attractive candidates for solar physics instrumentation and for other applications.
The catalytic mechanism for aerobic formation of methane by bacteria

Methane is a potent greenhouse gas that is produced in significant quantities by aerobic marine organisms. These bacteria apparently catalyse the formation of methane through the cleavage of the highly unreactive carbon-phosphorus bond in methyl phosphonate (MPn), but the biological or terrestrial source of this compound is unclear. However, the ocean-dwelling bacterium Nitrosopumilus maritimus catalyses the biosynthesis of MPn from 2-hydroxyethyl phosphonate and the bacterial C-P lyase complex is known to convert MPn to methane. In addition to MPn, the bacterial C-P lyase complex catalyses C-P bond cleavage of many alkyl phosphonates when the environmental concentration of phosphate is low. PhnJ from the C-P lyase complex catalyses an unprecedented C-P bond cleavage reaction of ribose-1-phosphonate-5-phosphate to methane and ribose-1,2-cyclic-phosphate-5-phosphate. This reaction requires a redox-active [4Fe-4S]-cluster and S-adenosyl-L-methionine, which is reductively cleaved to L-methionine and 5'-deoxyadenosine. Here we show that PhnJ is a novel radical S-adenosyl-L-methionine enzyme that catalyses C-P bond cleavage through the initial formation of a 5'-deoxyadenosyl radical and two protein-based radicals localized at Gly 32 and Cys 272. During this transformation, the pro-R hydrogen from Gly 32 is transferred to the 5'-deoxyadenosyl radical to form 5'-deoxyadenosine and the pro-S hydrogen is transferred to the radical intermediate that ultimately generates methane. A comprehensive reaction mechanism is proposed for cleavage of the C-P bond by the C-P lyase complex that uses a covalent thiophosphate intermediate for methane and phosphate formation.
Unsteady heat and mass transfer with phase change in porous slabs: analytical solutions and experimental results

Abstract Unsteady one-dimensional heat and mass transfer with phase change in a porous slab is analytically investigated. It is shown that for a large class of problems the rate of motion of the wet zone can be decoupled from the transient change in the temperature and species fields, and the unsteady process can be reduced to that of quasi-steady fields in time-dependant domains. Analytical results are presented for mobile and immobile condensates. Reasonable agreement between the analytical solutions and experimental data is obtained.
Effect of composition on the properties of strain-transformable β titanium alloys

A number of metastableβ titanium alloys were examined to determine the effects of composition on strain-transformation behavior and precipitation hardening response. Maximum ductility as solution heat treated was observed in alloys slightly richer in alloy content than the minimum alloy content required to retain an all-β microstructure on quenching. Such materials transformed to a martensitic structure upon straining and, as a result of strain transformation, developed room temperature ductility exceeding that found in unalloyed titanium. Uniform elongation of 35 to 45 pct was observed in a number of compositions of this type containing major additions of Mo, V, Cr, or Mn. Auxiliary alloy additions of Sn, Al, or Zr, or ternary alloying with molybdenum were necessary to preventω embrittlement during quenching in alloys containing V, Cr, or Mn. Alloying with Fe, Cu, Co, or Ni resulted in low ductility as solution heat treated, but it is probable that optimum amounts of these additions were not studied in this investigation. Oxygen above about 1200 ppm also had a detrimental effect on ductility. All alloys studied showed precipitation hardening when heat treated in the 800° to 1100°F range. Tensile strengths of 170 to 190 ksi were readily attainable in most alloy systems. Ductility as precipitation hardened appeared to be higher in alloys containing at least 6 pct Mo or V than in other alloys studied.
Second‐generation effects of unresolved trauma in nonmaltreating parents: Dissociated, frightened, and threatening parental behavior

(1999). Second‐generation effects of unresolved trauma in nonmaltreating parents: Dissociated, frightened, and threatening parental behavior. Psychoanalytic Inquiry: Vol. 19, Attachment Research and Psychoanalysis: 1. Theoretical Considerations, pp. 481-540.
Toxicity of parathion to captive european starlings (Sturnus vulgaris) — absence of seasonal effects

The effects of season on the toxicity of the prototypic organophosphorus insecticide parathion was evaluated using adult European starlings (Sturnus vulgaris) housed in outdoor pens. Groups of birds received oral doses of parathion in the fall, winter, spring and summer. Median lethal dosage, and brain and plasma cholinesterase inhibition, were found to be quite similar among seasons. Parathion may have been more toxic during hot weather (winter vs. summer LD50 estimate: 160 vs. 118 mg/kg; p < 0.1). In view of previous reports in which ambient temperature extremes and harsh weather have enhanced organophosphorus insecticide toxicity to birds, it is concluded that circannual toxicity studies should include measures of sensitivity (acute oral exposure) and vulnerability (dietary exposure) to better predict responses of free-ranging birds.
The economics of biosphere reserves and the conservation of forest genetic resources

Abstract The economic evaluation of the gene bank component of a biosphere reserve project is one of the requirements before deciding to preserve an area. The direct and measurable benefits, together with the unmeasurable benefits, have to be weighted against the cost of the best forgone development alternative to determine if the preservation project is to be implemented. The safe minimum standard of conservation criterion is discussed. The decision is made in the midst of great uncertainties and possible irreversibilities. A conservative policy allowing maximum flexibility in the future and a close monitoring of the project is recommended.
MIMO-FEA for Design and Active Vibration Suppression of an Adaptive Circular Composite Plate

Adaptive structures combine sensors, actuators, and control systems for intelligent responses to their environment and promise a novel approach to satisfying the stringent performance requirements of future aerospace and space applications. This study focuses on a multi-input-multi-output finite element analysis for the design and active vibration suppression of an adaptive circular composite plate used here as the top device-plate for an intelligent composite platform that is designed for thrust vector control of a satellite thruster. The adaptive circular composite plate has three pairs of back-to-back embedded piezoelectric active fiber composite actuator patches. A finite element harmonic analysis is employed to develop a vibration suppression scheme, which is then used to study the vibration suppression of the circular composite plate using the piezoelectric patches embedded in the plate. In this approach, the responses of the structure to an arbitrary external force as well as an arbitrary internal piezoelectric control voltage are first determined, individually. Using the linearity of the system, the responses are then assembled in a system of equation as a coupled system and then solved simultaneously to determine the control voltages and their respective phases for the system actuators for a given external disturbance. This approach is an effective technique for the design of smart structures with complex geometry and multi-input-multi-output sensor and actuator systems to study their active vibration suppression capabilities and effectiveness. The design and active vibration suppression of the adaptive circular composite plate are explained and discussed.© 2006 ASME
Color- and shape-tunable colloidal nanoparticles capable of nanopatterning

Color- and shape-tunable nanoparticles consisting of phase-separated copolymers within each particle were synthesized using emulsion copolymerization synthesis. Each particle consists of two phases: (1) poly(methyl methacrylate/n-butylacrylate) (p(MMA/nBA)) phase, which is responsible for a particle shape control, and (2) poly(n-butylacrylate/pentafluorostyrene/N,N-dimethyl aminoazoaniline methacrylate) (p(nBA/PFS/DMAAZOAMm)) phase, facilitating tunable color changes and fluorescence emission induced by acidic/basic environments. Since these particles are capable of coalescence, these studies also show simple nano-deposition process will result in ∼200–300 nm width nanowires with “polka-dot” morphologies, offering many diversified applications ranging from high-resolution inexpensive display technologies to nano-sensing devices, or multi-drug and multi-transient delivery systems.
An analysis of GCFR depressurization transients without scram

Abstract Four transients imposed on a gas cooled fast breeder reactor (GCFBR or GCFR) plant are analyzed. The transients are variations of a design basis depressurization accident (DBDA) [1], in which a rupture is postulated in the inlet plenum, the reactor is scramed and the circulator output is drastically reduced. Variations considered are, (1) in all cases the reactor is not scrammed; and (2) the rupture size is varied from 0.6 ft 2 to zero. In the limit of zero (no rupture) the transient imposed on the system is due to the behavior of the circulator and steam generator during a DBDA.
Empirical analysis of programming language adoption

Some programming languages become widely popular while others fail to grow beyond their niche or disappear altogether. This paper uses survey methodology to identify the factors that lead to language adoption. We analyze large datasets, including over 200,000 SourceForge projects, 590,000 projects tracked by Ohloh, and multiple surveys of 1,000-13,000 programmers.We report several prominent findings. First, language adoption follows a power law; a small number of languages account for most language use, but the programming market supports many languages with niche user bases. Second, intrinsic features have only secondary importance in adoption. Open source libraries, existing code, and experience strongly influence developers when selecting a language for a project. Language features such as performance, reliability, and simple semantics do not. Third, developers will steadily learn and forget languages. The overall number of languages developers are familiar with is independent of age. Finally, when considering intrinsic aspects of languages, developers prioritize expressivity over correctness. They perceive static types as primarily helping with the latter, hence partly explaining the popularity of dynamic languages.
Tussock Tundra Albedos on the North Slope of Alaska: Effects of Illumination, Vegetation Composition, and Dust Deposition

Abstract The albedo of tussock tundra was measured at two sites on the north slope of Alaska. One site was selected because of its apparent uniformity and undisturbed condition, while the other site had been visibly affected by dust deposition from the Dalton Highway. Albedo measurements were made under varying cloud-cover conditions. It was hypothesized that observed variations in albedo at the undisturbed site were caused by variations in illumination conditions and ventilation cover type. A simple cloud index (CI) was used to characterize the cloud-cover-illumination conditions, and vegetation cover was described using a hierarchical classification scheme and point-guadrat sampling. Albedo at the undisturbed site was found to be related significantly to variations in CI but unaffected by differences in vegetation cover type. The final component of the study compared the albedo-CI relationships at the undisturbed and dust-impacted sites. It was concluded that dust deposition had a significant direct and...
Stable Isotope Probing:Linking Functional Activity to Specific Members of Microbial Communities

Linking organisms or groups of organisms to specific functions within natural environments is a fundamental challenge in microbial ecology. Advances in technology for manipulating and analyzing nucleic acids have made it possible to characterize the members of microbial communities without the intervention of laboratory culturing. Results from such studies have shown that the vast majority of soil organisms have never been cultured, highlighting the risks of culture-based approaches in community analysis. The development of culture-independent techniques for following the flow of substrates through microbial communities therefore represents an important advance. These techniques, collectively known as stable isotope probing (SIP), involve introducing a stable isotope-labeled substrate into a microbial community and following the fate of the substrate by extracting diagnostic molecular species such as fatty acids and nucleic acids from the community and determining which specific molecules have incorporated the isotope. The molecules in which the isotope label appears provide identifying information about the organism that incorporated the substrate. Stable isotope probing allows direct observations of substrate assimilation in minimally disturbed communities, and thus represents an exciting new tool for linking microbial identity and function. The use of lipids or nucleic acids as the diagnostic molecule brings different strengths and weaknesses to the experimental approach, and necessitates the use of significantly different instrumentation and analytical techniques. This short review provides an overview of the lipid and nucleic acid approaches, discusses their strengths and weaknesses, gives examples of applications in various settings, and looks at prospects for the future of SIP technology.
Maternal bias and escape from X chromosome imprinting in the midgestation mouse placenta

To investigate the epigenetic landscape at the interface between mother and fetus, we provide a comprehensive analysis of parent-of-origin bias in the mouse placenta. Using F1 interspecies hybrids between mus musculus (C57BL/6J) and mus musculus castaneus, we sequenced RNA from 23 individual midgestation placentas, five late stage placentas, and two yolk sac samples and then used SNPs to determine whether transcripts were preferentially generated from the maternal or paternal allele. In the placenta, we find 103 genes that show significant and reproducible parent-of-origin bias, of which 78 are novel candidates. Most (96%) show a strong maternal bias which we demonstrate, via multiple mathematical models, pyrosequencing, and FISH, is not due to maternal decidual contamination. Analysis of the X chromosome also reveals paternal expression of Xist and several genes that escape inactivation, most significantly Alas2, Fhl1, and Slc38a5. Finally, sequencing individual placentas allowed us to reveal notable expression similarity between littermates. In all, we observe a striking preference for maternal transcription in the midgestation mouse placenta and a dynamic imprinting landscape in extraembryonic tissues, reflecting the complex nature of epigenetic pathways in the placenta.
Treatment of Atypical Mycobacterial Disease

The most common disease patterns produced by atypical mycobacteria are pulmonary disease, cervical lymphadenitis, and infection of soft tissue, bones, and joints. The treatment of disease due to atypical mycobacteria can be confusing unless one clearly differentiates the organisms according to clinical characteristics and response to various chemotherapeutic agents. For this reason, we have attempted to simplify the task by proposing a new classification system. The organisms that might be isolated from human material are divided into the following three classes: nonpathogens; those that are easy to treat with standard mycobacterial therapy; and finally, those that are difficult to treat with standard mycobacterial therapy and require other approaches. This new system of classification should help the clinician in dealing with these organisms. Because even the pathogens may sometimes appear as a contaminant in human material, including sputum, one must document that these organisms are associated with disease prior to instituting therapy.
Glass structure: The bridge between the molten and crystalline states

The structural-chemical basis is developed for Ti4+ occupancy of Si4+ sites in the vitreous silica continuous random network (C.R.N.). The limit for an isostructural family of glasses is calculated in terms of the population density of cation-near neighbor cation configurations. These quantitatively define randomness and also link the molecular scale of structure with the macroscopic scale of thermo-dynamics and bulk properties. All measured properties agree with theoretical predictions.
The effect of medium and long chain triglyceride on human adipose tissue metabolism.

Studies have been performed to assess the effects, in vivo and in vitro, of lipid emulsions on human adipose tissue prostaglandin production. Subcutaneous adipose tissue obtained either during elective surgery or by needle aspiration was studied in tissue culture or by using a perifusion apparatus. Physical mixtures of emulsions of long chain triglyceride (LCT) and/or medium chain triglyceride (MCT) were added to the tissue culture medium so that the final concentration was 400 mg/dl. After a 3-day incubation period the tissue was harvested, placed in buffer and used to determine in vitro production of prostaglandin E2, prostacyclin I2 (measured as its stable end product 6-keto PGF1α) and thromboxane A2 (measured as TXB2) by radioimmunoassay. The results demonstrated that samples incubated in 100% MCT had the most significant increase in prostaglandin production, while those incubated in 100% LCT had the most significant decrease in activity of the three prostaglandins assayed. The addition of LCT to MCT caused a stepwise decrease in adipose tissue prostaglandin production. The data suggest a pharmacological rather than a physiological effect of lipid emulsions containing MCT and/or LCT on adipose tissue prostaglandin production. In vivo effects of a 20% safflower oil emulsion, containing high levels of the essential fatty acid linoleate, were assessed in five pediatric patients. Adipose tissue was obtained before and after two and four weeks of treatment. Fatty acid profiles and prostaglandin production were determined. The results demonstrated that intravenous fat infusion increased the concentrations of linoleic and arachidonic acids found in adipose tissue within a short interval. The effect of intravenous fat infusion on human adipose tissue prostaglandin production was less predictable and may have been a function of the patients' disease and subsequent clinical course. These findings suggest that lipid emulsions should not be viewed solely as a source of intravenous energy, because they may have the potential to elicit changes in prostaglandin production as demonstrated by a human adipose tissue model.
Dynamic Formation and Breaking of Disulfide Bonds in Molecular Dynamics Simulations with the UNRES Force Field.

Many proteins contain disulfide bonds that are usually essential for maintaining function and a stable structure. Several algorithms attempt to predict the arrangement of disulfide bonds in the context of protein structure prediction, but none can simulate the entire process of oxidative folding, including dynamic formation and breaking of disulfide bonds. In this work, a potential function developed to model disulfide bonds is coupled with the united-residue (UNRES) force field, and used in both canonical and replica exchange molecular dynamics simulations to produce complete oxidative folding pathways. The potential function is obtained by introducing a transition barrier that separates the bonded and nonbonded states of the half-cystine residues. Tests on several helical proteins show that improved predictions are obtained when dynamic disulfide-bond formation and breaking are considered. The effect of the disulfide bonds on the folding kinetics is also investigated, particularly their role in stabiliz...
Effect of Group Heterogeneity on Quality of Task Solutions

Subjects were placed into groups on the basis of either trait homogeneity or heterogeneity with the other group members and were given a group task to complete. The results indicated group answers of superior quality when the group was composed of heterogeneous individuals rather than homogeneous individuals.
Objects, Processes, and Female Infertility in Chinese Medicine

Focusing on the diagnosis and treatment of female infertility in traditional Chinese medicine's “women's specialty” (fu ke), I examine the relationship between anatomical objects or substances and physiological processes in Chinese medical analysis. After considering the significance of gender in medical perception, I cite field observations, textbook explanations, and published cases to illustrate a bias toward the temporal and the processual in Chinese medicine. Continuities between illness experiences and understandings of women's bodies are explored in relation to these clinical modes of knowing.
Limitations and potentials of current motif discovery algorithms

Computational methods for de novo identification of gene regulation elements, such as transcription factor binding sites, have proved to be useful for deciphering genetic regulatory networks. However, despite the availability of a large number of algorithms, their strengths and weaknesses are not sufficiently understood. Here, we designed a comprehensive set of performance measures and benchmarked five modern sequence-based motif discovery algorithms using large datasets generated from Escherichia coli RegulonDB. Factors that affect the prediction accuracy, scalability and reliability are characterized. It is revealed that the nucleotide and the binding site level accuracy are very low, while the motif level accuracy is relatively high, which indicates that the algorithms can usually capture at least one correct motif in an input sequence. To exploit diverse predictions from multiple runs of one or more algorithms, a consensus ensemble algorithm has been developed, which achieved 6–45% improvement over the base algorithms by increasing both the sensitivity and specificity. Our study illustrates limitations and potentials of existing sequence-based motif discovery algorithms. Taking advantage of the revealed potentials, several promising directions for further improvements are discussed. Since the sequence-based algorithms are the baseline of most of the modern motif discovery algorithms, this paper suggests substantial improvements would be possible for them.
Folate intake, alcohol use, and postmenopausal breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Background Several epidemiologic studies suggest that higher folate intakes are associated with lower breast cancer risk, particularly in women with moderate alcohol consumption. Objective We investigated the association between dietary folate, alcohol consumption, and postmenopausal breast cancer in women from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort. Design Dietary data were collected at study enrollment between 1993 and 2001. Folate content was assigned on the basis of prefortification (ie, pre-1998) databases. Of the 25 400 women participants with a baseline age of 55-74 y and with complete dietary and multivitamin information, 691 developed breast cancer between September 1993 and May 2003. We used Cox proportional hazard models with age as the underlying time metric to generate hazard ratios (HRs) and 95% CIs. Results The adjusted HRs were 1.19 (95% CI: 1.01, 1.41; P for trend = 0.04) for women reporting supplemental folic acid intake >/=400 mug/d compared with subjects reporting no supplemental intake. Comparison of the highest with the lowest quintile gave adjusted HRs of 1.04 (95% CI: 0.83, 1.31; P for trend = 0.56) and 1.32 (95% CI: 1.04, 1.68; P for trend = 0.03) for food and total folate intake, respectively. Alcohol consumption was positively associated with breast cancer risk (highest compared with lowest quintile: HR = 1.37; 95% CI: 1.08, 1.76; P for trend = 0.02); the risk was greatest in women with lower total folate intake. Conclusions Our results do not support the hypothesis that high folate intake reduces breast cancer risk; instead, they suggest that a high intake, generally attributable to supplemental folic acid, may increase the risk in postmenopausal women. However, our results confirm previous studies showing positive associations between moderate alcohol consumption and breast cancer.
Yield, nutritive value and silage fermentation of kura clover-reed canarygrass and lucerne herbages in northern USA

Excellent winter hardiness, persistence and nutritive value of both kura clover (Trifolium ambiguum M. Bieb.) and reed canarygrass (Phalaris arundinacea L.) suggest that intercropping these species could substitute for lucerne (Medicago sativa L.). The dry matter (DM) yield and nutritive value of herbage, and silage characteristics of kura clover-reed canarygrass (KC-RCG) herbage, were compared to those of lucerne over two growth cycles near Arlington, WI, USA. First and second growths of lucerne and KC-RCG herbage were sampled four times at 1-week intervals and ensiled for 100 d. Yield of DM of the KC-RCG was 0·23–0·57 greater than that of lucerne on sampling dates in the first growth cycle, with no differences in DM yield in the second growth cycle. The pH of lucerne silage was lower than that of KC-RCG silage in the first growth, and the opposite occurred in second growth, which was attributed to maturity differences and the proportion of kura clover in the mixture. Lactate concentration was lower in KC-RCG than lucerne silages in both growth cycles. The lucerne and KC-RCG silages had similar in vitro DM digestibility except for the final sampling date in the first growth cycle when neutral-detergent fibre concentration of KC-RCG herbage exceeded 550 g kg−1 DM. Crude protein concentration was greater in lucerne silage than in KC-RCG silage in both growth cycles. Overall, differences in nutritive value and silage fermentation between the two herbages were minimal across growth cycles. These results suggest that a KC-RCG sward is a viable alternative to lucerne in northern environments of the USA where lucerne production may be limited by winter injury or edaphic factors.
Fish otolith trace element maps: new approaches with synchrotron microbeam x-ray fluorescence

Otoliths, the carbonate earstones of fishes, take up minor and trace amounts of elements as they accrete through a fish's life. We apply synchrotron microbeam x-ray fluorescence methods to establish a breakthrough in high-resolution, simultaneous area mapping of multiple trace elements in otoliths, with spatial resolution down to 20 µm and trace element detection down into the part per million range for multiple elements. Concentration maps of Ca, Sr, Zn and, for the first time, Ba, Mn, and Se are obtained simultaneously. Combinations of these elemental maps provide new insights into the environmental history of fishes and their lifetime movements, illustrated by several case studies. This method helps pave the way toward improved spatial analysis of otolith microchemistry. Copyright © 2007 John Wiley & Sons, Ltd.
Parental Status and Subjective Well-Being Among Currently Married Individuals in China

Using data from the 2006 Chinese General Social Survey (N = 2,515), we examine the relationship between parental status and subjective well-being among Chinese adults who are in their first marriages. After accounting for background characteristics, parents and childless individuals do not report significantly different feelings of well-being. When parental status is disaggregated according to family structure, parents of adult children only report higher levels of subjective well-being than both parents of minor children and the childless. The number of daughters is positively associated with feelings of well-being. Furthermore, the effects of coresiding with adult children appear to depend on whether one has minor children in the household. Coresident adult children are positively associated with well-being when minor children are also present but are negatively associated with well-being when minor children are not present.
Discrete versus cumulative dosing in dose–response discrimination studies

This study describes the results of a 'side-by-side' comparison of two measurement techniques and two dosing regimens in a . discrimination study using rats trained to either 10 mgrkg cocaine or 2 mgrkg 3,4-methylenedioxymethamphetamine MDMA . The measurements employed were either quantal or quantitative; the former an all-or-none correct lever selection measure and the latter a measure of all responses made at the time that the criterion for selection was met. The dosing regimens were either a discrete single injection of lower doses than used in training or a cumulative dose administration sequence, in an ascending order, during one session on two separate occasions. Results indicate that the cumulative dose-response relationships, as indicated by both the slope of the curve or the generated ED value, for the discrete and cumulative dose-response curves do not significantly differ. In addition, both the quantal 50 and quantitative measurements yield almost identical ED values, thus allowing for accurate comparability of drug-discrimination data 50 using different techniques. The present experimentation employed two drugs known to produce heightened response rates which would not allow for behavioral suppression at the highest doses used either in discrete or cumulative regimens. The pharmacokinetics of the two drugs employed in the discrimination tests are considered and discussed in light of the advantages and disadvantages of each of the two methods employed. . .
The splicing regulator PTBP2 interacts with the cytidine deaminase AID and promotes binding of AID to switch-region DNA

The cytidine deaminase AID is essential for the immunoglobulin-diversification processes. Chaudhuri and colleagues identify the splicing factor PTBP2, which promotes the binding of AID to switch-region DNA.