cssi/SciSciGPT-SciSciNet huggingface dataset:
Anderson impurity in a semiconductor.

We study an Anderson impurity in a semiconducting host using the density matrix renormalization group technique. We use the U=0 one-dimensional Anderson Hamiltonian at half filling as the semiconducting host since it has a hybridization gap. By varying the hybridization of the host, we can control the size of the semiconducting gap \ensuremath{\Delta}. We consider chains with 25 sites and we place the Anderson impurity (with U\ensuremath{\gtrsim}0) in the middle of the chain. We dope the half-filled system with one hole and we find two regimes: when the hybridization of the impurity is small such that the energy \ensuremath{\Delta}E to add a hole to the impurity site is less than \ensuremath{\Delta}/2, the hole density and the spin are localized near the impurity. When the hybridization of the impurity is large (\ensuremath{\Delta}E\ensuremath{\gtrsim}\ensuremath{\Delta}/2), the hole and spin density are spread over the lattice. Additional holes avoid the impurity and are extended throughout the lattice. Away from half filling, the semiconductor with an impurity is analogous to a double well potential with a very high barrier. We also examine the chemical potential as a function of electron filling, and we find that the impurity introduces midgap states when the impurity hybridization is small. \textcopyright{} 1996 The American Physical Society.
The avian sarcoma virus PRCII lacks 1020 nucleotides of the fps transforming gene.

Abstract Fujinami sarcoma virus (FSV) and PRCII avian sarcoma virus both encode gag-fps transforming proteins associated with tyrosine-specific protein kinase activity; however, PRCII has a lower oncogenic potential than does FSV. In this study, the genomes of PRCII and FSV have been compared. By hybridization of PRCII [ 32 P]RNA to FSV DNA on Southern blots, a large internal deletion in the 5′ half of the fps gene in PRCII has been mapped. To determine the exact size and location of the deletion in PRCII, dideoxy sequencing of PRCII RNA with FSV DNA fragments as primers was used. The FSV sequence corresponding to the deletion in PRCII was flanked by 6-base direct repeats (AGCTGG) at 1614–1619 and 2634–2639 nucleotides. One copy of the direct repeat was retained in the PRCII genome. The length of the deleted region was 1020 nucleotides. The deletion in fps did not alter the kinase domain or ATP-binding site of the P105 transforming protein of PRCII. It was shown that the specific kinase activity of P105 was as high as that of FSV P130. The sequence deleted from PRCII was found to encode part of a large hydrophilic domain. In the accompanying paper [ J. Woolford and K. Beemon (1984) Virology 135 , 168–180], evidence that the PRCII and FSV proteins have different subcellular locations and solubility properties, possibly due to the loss of this domain, is presented. These alterations in the structure and location of the PRCII protein may prevent it from phosphorylating certain substrates involved in oncogenic transformation.
Geometrical branching model: Phenomenology with jets

The geometrical branching model with jets is used to analyze the data on sigma/sub el/,sigma/sub tot/,, and the higher moments of particle multiplicity in hadron-hadron collisions at all available energies. The eikonal formalism is used as the framework to combine the soft and hard components of the multiparticle production process. The soft component of the eikonal function is assumed to be geometrical scaling even in the presence of the hard component. We show in the context of the model that the geometrical size of a hadron ceases to increase in the energy region of the CERN Spp-barS collider. The production of jets is shown to be responsible not only for the continued increase of the inelastic cross section, but also for the breaking of the Koba-Nielson-Olesen scaling.
Risk-Based Management of Contaminated Sediments: Consideration of Spatial and Temporal Patterns in Exposure Modeling

This paper addresses interactions among foraging behavior, habitat preferences, site characteristics, and spatial distribution of contaminants in developing PCB exposure estimates for winter flounder at a hypothetical open water dredged material disposal site in the coastal waters of New York and New Jersey (NY−NJ). The implications of these interactions for human health risk estimates for local recreational anglers who fish for and eat flounder are described. The models implemented in this study include a spatial submodel to account for spatial and temporal characteristics of fish exposures and a probabilistic adaptation of the Gobas bioaccumulation model that accounts for temporal variation in concentrations of hydrophobic contaminants in sediment and water. We estimated the geographic distribution of a winter flounder subpopulation offshore of NY−NJ based on species biology and its vulnerability to local recreational fishing, the foraging area of individual fish, and their migration patterns. We incorp...
Transition to a Transit City: Case of Beijing

Over the past three decades, the urban transportation system in Beijing has been undergoing tremendous changes. Beijing has been transformed from a city dominated by nonmotorized transportation to an almost car-saturated city. To combat the ever-growing traffic gridlock, the city in recent years has been working proactively on fulfilling its long-term vision: building a transit city. This study presents the city's development of a more sustainable transportation system from a mobility culture perspective. More specifically, the focus is on these three aspects: travel demand, mobility patterns, and transportation policy.
From HIV to global health: opportunities and challenges

Remarkable advances have been achieved over the past decade in confronting the global HIV epidemic. By the end of 2010, 6.5 million persons living with HIV had initiated antiretroviral therapy in low and middle-income countries, the majority in sub Saharan Africa. Of the total of 2.5 new HIV infections that occurred in 2010, 1.9 million occurred in sub Saharan Africa. Nonetheless, 22 countries in sub Saharan Africa have experienced a decrease in HIV incidence. These remarkable achievements have involved a transformation of fragile health system. Examples include new models of care, task shifting, infrastructure enhancement, establishment of new data systems and mobilization of communities. However, many of the same countries where HIV is prevalent also confront other health threats including high maternal and child mortality, high rates of tuberculosis and malaria as well as a burgeoning non-communicable chronic disease threat. Addressing these health threats requires taking the lessons learned from the HIV response and adapting them to confront these threats. Through building on the foundation established, similar progress may be achieved in addressing these health threats while maintaining the momentum of the HIV response.
Linking tricyclic antidepressants to ionotropic glutamate receptors.

Although tricyclic antidepressants have been in existence since the 1940s when they were discovered upon screening iminodibenzyl derivatives for other potential therapeutic uses, their mechanism of action has remained unclear [A. Goodman Gilman, T.W. Rall, A.S. Nies, P. Taylor, Goodman and Gilman’s The Pharmacological Basis of Therapeutics, eighth ed., Pergamon Press, New York, 1990]. In addition to their ability to hinder the reuptake of biogenic amines, there is mounting evidence that the tricyclic antidepressants inhibit glutamate transmission. Here, intrinsic tryptophan fluorescence spectroscopy is used to document the binding of desipramine, a member of the tricyclic antidepressant family, to a well-defined extracellular glutamate binding domain (S1S2) of the GluR2 subunit of the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor. The binding is distinct from those of other known effectors of the receptor, including the endogenous sulfated neurosteroids pregnenolone sulfate and 3α-hydroxy-5β-pregnan-20-one sulfate, and is consistent with a conformational change upon binding that is allosterically transmitted to the channel region of the receptor.
Filter-based calibration for an IMU and multi-camera system

Vision-aided Inertial Navigation Systems (vINS) are capable of providing accurate six degree of freedom (6DoF) state estimation for autonomous vehicles (AVs) in the absence of Global Positioning System (GPS) and other global references. Features observed by a camera can be combined with measurements from an inertial measurement unit (IMU) in a filter to estimate the desired vehicle states. To do so, the rigid body transformation between cameras and the IMU must be known with high precision. Extended Kalman filters (EKF) and Unscented Kalman filters (UKF) have been used to calibrate camera and IMU systems requiring only a simple calibration target and moderate IMU-camera motion. This paper focuses on indoor applications where it is assumed a user is able to easily manipulate the sensor package. We extend the UKF filter to calibrate an IMU paired with an arbitrary number of cameras, with or without overlapping fields of view.
Fabrication of gold nanoparticles for targeted therapy in pancreatic cancer

The targeted delivery of a drug should result in enhanced therapeutic efficacy with low to minimal side effects. This is a widely accepted concept, but limited in application due to lack of available technologies and process of validation. Biomedical nanotechnology can play an important role in this respect. Biomedical nanotechnology is a burgeoning field with myriads of opportunities and possibilities for advancing medical science and disease treatment. Cancer nanotechnology (1-100 nm size range) is expected to change the very foundations of cancer treatment, diagnosis and detection. Nanomaterials, especially gold nanoparticles (AuNPs) have unique physico-chemical properties, such as ultra small size, large surface area to mass ratio, and high surface reactivity, presence of surface plasmon resonance (SPR) bands, biocompatibility and ease of surface functionalization. In this review, we will discuss how the unique physico-chemical properties of gold nanoparticles may be utilized for targeted drug delivery in pancreatic cancer leading to increased efficacy of traditional chemotherapeutics.
Receptive Vocabulary in Boys with Autism Spectrum Disorder: Cross-Sectional Developmental Trajectories

In light of evidence that receptive language may be a relative weakness for individuals with autism spectrum disorder (ASD), this study characterized receptive vocabulary profiles in boys with ASD using cross-sectional developmental trajectories relative to age, nonverbal cognition, and expressive vocabulary. Participants were 49 boys with ASD (4–11 years) and 80 typically developing boys (2–11 years). Receptive vocabulary, assessed with the Peabody Picture Vocabulary Test, was a weakness for boys with ASD relative to age and nonverbal cognition. Relative to expressive vocabulary, assessed with the Expressive Vocabulary Test, receptive vocabulary increased at a lower rate for boys with ASD. Vocabulary trajectories in ASD are distinguished from typical development; however, nonverbal cognition largely accounts for the patterns observed.
NETI: the NeuroEngineering Training Initiative

Summary form only given. Neuroengineering is defined as the interdisciplinary field of engineering and computational approaches, as applied to problems in basic and clinical neuroscience. The NeuroEngineering Training Initiative at Johns Hopkins seeks to balance engineering, mathematics, and computer science with molecular, cellular, and systems neurosciences. The program leverages the educational and research resources of both the engineering and medical schools. The life sciences training consists of courses taught either through the medical school or through the basic biomedical science curriculum. The engineering training consists of rigorous coursework in mathematics, computation, and other engineering subjects appropriate for the particular student's focus. NETI trainees also forge collaborations between faculty members, participate in weekly seminars, and present their research at various conferences. Through schoolwork, seminars, social events, conferences, and collaborative interactions, our students provide the nexus between basic science, clinical, and engineering research. The NIH has recognized the importance of this initiative and has provided funding for the program. NETI trainees have the unique opportunity to be part of the pioneer program in neuroengineering training while taking advantage of the world class institution that is Johns Hopkins
Large-scale expansion in interleukin-2 of tumor-infiltrating lymphocytes from patients with ovarian carcinoma for adoptive immunotherapy

Tumor infiltrating lymphocytes (TIL) from malignant ascites or solid tumor specimens obtained from patients with ovarian carcinoma were expanded to large numbers in vitro (10(10)-10(11)) by a four-step method using AIM V medium and low concentrations of recombinant interleukin-2 (rIL-2). The expansion procedure employed 24-well culture plates, T-flasks, polyolefin gas-permeable bags (PGPB), and an artificial capillary culture system (ACCS). The mean number of mononuclear leukocytes introduced into the 24-well plates was 16.5 +/- 4.2 x 10(6) cells. TIL from a total of 16 patients were expanded only through the first three steps of the process (24-well-plates, T-flasks, and PGPB) with an overall expansion of 255 +/- 99 fold and mean duration of 27.4 +/- 2.2 days. TIL from 9 of 16 patients were expanded further through the fourth step (ACCS) of the expansion method. The cumulative fold-expansion in nine patients was 8044 +/- 4807 (mean +/- SEM), the median was 2876 and the mean expansion time was 47.1 +/- 4.7 days. TIL from seven additional patients did not grow in rIL-2. Six of these 7 patients received chemotherapy at least four weeks before the specimens were collected. Two ACCS were used in parallel to facilitate expansion of TIL. Viable rIL-2-expanded TIL in the range of 1 x 10(10)-1 x 10(11) were recovered from the two ACCS, a number sufficient for adoptive immunotherapy of patients with ovarian carcinoma. The rIL-2-expanded TIL were predominantly CD3+ CD4+ CD8- alpha beta TCR+, although CD3+ CD4- CD8+ alpha beta TCR+ T cell lines were obtained from certain patients. An increase (43 +/- 8 vs 75 +/- 13; P = 0.05) in the proportion of CD4+ cells was observed over the duration of the four expansion steps. However, CD8+ TIL-derived T cells lines were also expanded in the ACCS. The four-step expansion method described here has several significant advantages over existing techniques. It requires substantially less personnel, equipment and space and the risk of contamination during expansion of the cultures is decreased. These results demonstrate that the four-step method described here can be effectively used for the large-scale expansion of ovarian TIL for the treatment of patients with ovarian carcinoma by adoptive immunotherapy.
Studies on Taxadiene Synthase: Interception of the Cyclization Cascade at the Isocembrene Stage with GGPP Analogues

[reaction: see text] The cyclization of GGPP to taxadiene, catalyzed by taxadiene synthase, has been suggested to proceed through a series of monocyclic isocembrenyl- and bicyclic verticillyl-carbocationic intermediary stages. A set of GGPP analogues with abolished or perturbed pi-nucleophilicity at the delta10 double bond (GGPP numbering) was synthesized and incubated with taxadiene synthase to intercept the cyclization cascade at the monocyclic stage. Each analogue was transformed by taxadiene synthase in vitro to hydrocarbon products in varying yields, and the structures of the major product in each reaction were solved by GCEIMS and one- and two-dimensional (1H and 13C) NMR and found to be 14-membered monocyclic isocembrenyl diterpenes, indicating that the first C-C bond formation catalyzed by taxadiene synthase could be uncoupled from the other subsequent bond formation events by using suitably designed substrate analogues. The formation and isolation of these isocembrenyl diterpene products using taxadiene synthase supports proposals that the isocembrenyl cation is an intermediate in the cyclization of GGPP to taxadiene.
Effects of Bird Density, Nutrient Density and Perches on the Performance of Caged White Leghorn Layers

Abstract SEVERAL studies have compared cage size and bird density with 1 to 5 hens per cage (Lowe and Heywang, 1964; Wilson et al., 1964, 1967; Blount, 1965; Moore et al., 1965; Owings et al., 1967; Ruggles et al., 1967; Champion and Zindel, 1968; Shirley, 1969; Ostrander and Young, 1969). Bramhall et al. (1966) and Quisenberry (1968) summarized several studies and concluded that small cages with 2 to 5 hens per cage providing 350 to 465 square centimeters (sq. cm.) per hen are usually more suitable than larger cages providing similar space per bird. Most studies show that 1 hen per cage usually performs best, but beyond that the results vary. There is often a decline, either significant or non-significant, in egg production and an increase in mortality as the space per bird decreases. Wilson et al. (1964, 1967) found only part of the increase in mortality to be due to…
Vacancies and vacancy clusters in shock‐loaded molybdenum: Direct observations by transmission electron and field‐ion microscopy

A novel experimental sandwich arrangement of molybdenum thin sheets and wires was shock‐loaded at a pressure of 150 kbar (for 2 μsec), and thin foils and emission end forms prepared from these samples were simultaneously examined by transmission electron and field‐ion microscopy, respectively. Dislocation loop densitis were observed to be 5×109 cm−3 in the annealed foil samples as compared with 4×1014 cm−3 in the shock‐loaded foil samples, and 75% of the loop types analyzed were vacancy. The direct measurement of vacancy density in the field‐ion microscope revealed twice as many vacancies (including aggregates) in the shock‐loaded wires as compared with the annealed unshocked wires.
Estimation of tissue phospholipids by natural abundance 13C-NMR.

Abstract The total phospholipid content of excised rat muscle, liver, brain and kidney and of human muscle biopsies was estimated by natural abundance 13 C-NMR after complete solubilization of the tissue membranes with excess halothane. An external dioxane capillary, calibrated against pure palmitic acid and phospholipid vesicles with known phosphate concentration, was inserted into the tissues, and the repeating methylene carbon peak area in the spectra of the halothane-treated tissues was integrated versus the dioxane reference peak area. The amount of tissue used for NMR analysis was quantitated by dry weight determination after 13 C spectroscopy was completed. The phospholipid content estimated by the indirect NMR method was in good agreement with that measured by direct phosphate analysis and with literature data. For human muscle biopsies, the NMR method can also estimate the fraction of the total phospholipids which are mobile without treating the muscles with halothane. In this respect human muscles could be separated into three different groups: (1) normal and nonspecific muscle diseases, (2) myotonia and myopathy, (3) Duchenne dystrophy; with increasing fraction of the mobile phospholipids in this order.
Lymphosarcoma in a Brook Trout

A 2-yr-old female brook trout, Salvelinus fontinalis, maintained at a state fish hatchery in New York (USA) was culled from the breeding stock. At necropsy, it had a markedly enlarged kidney. On histopathological examination, lymphoblastic lymphoma was diagnosed in several organs including kidney, dorsal musculature, intestines, liver, gill, pseudobranch and ovary. Origin of the tumor was uncertain, although renal involvement could have been the primary site of development.
DNA content of Mauthner cell nuclei in Xenopus laevis: a spectrophotometric study.

The DNA content of individual Xenopus laevis Mauthner cell nuclei was measured by a spectrophotometric method. The Mauthner cell was found to contain a diploid amount of DNA as do VIIth nerve motor neurons and glial cells. The relationship of nuclear volume to ploidy is discussed with particular reference to neurons. It is concluded that no close correlation exists between these two factors when morphologically distinct types of neurons are compared. It is suggested that polyploidy of certain vertebrate neurons may be implicated more strongly in the metabolic activities involved in their function than in those concerned with their rapid initial growth.
Modeling the diurnal variation of ionospheric layers via Thom canonical potentials: time-frequency signatures

The A3 Thom canonical polynomial is used in a Newtonian gradient system to model the diurnal variation of ionospheric E and F layers. Time-frequency signatures of the plasma frequency variation over a scaled day are modeled.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
An estimation of aerodynamic forces and moments on an airplane model under steady state spin conditions

The problem of estimating the aerodynamic characteristics of a wing body configuration of a spinning airplane at extreme angles of attack and spin rates is approached by the application of strip theory. Semiempirical methods are used to estimate the aerodynamic force distributions over each component using static, nonrotational wind-tunnel test data. To these predictions, corrections are applied to account for the primary rotational flow effects which are significant at large spin rates. The results of this modified strip theory are shown to be in good agreement with spin tunnel rotary balance test data.
Active Thermochemical Tables: dissociation energies of several homonuclear first-row diatomics and related thermochemical values

The current Active Thermochemical Tables (ATcT) results for the bond dissociation energies of the homonuclear diatomics H2, C2, N2, O2, and F2 are reported and discussed. The role and origin of the distributed provenance of ATcT values is analyzed. Ramifications in terms of the enthalpies of formation of H, C, N, O, and F atoms, which are fundamental thermochemical quantities, are presented. In addition, the current ATcT bond dissociation energies and enthalpies of formation of HF, CH, CO, CN, NO, OH, CO2, H2O, and triplet and singlet CH2 are also reported.
Computational thermofracture mechanics and life prediction

Abstract This paper will present computational techniques used for the prediction of the thermofracture behaviour of structures subject to either monotonic or cyclic combined thermal and mechanical loadings. Two specific areas will be dealt with in the paper. (1) The Time-invariant thermofracture of leaking pipelines with non-uniform temperature fields: in this case, the induced non-uniform temperature fields near leaking cracks have shown to be significant. The severity of these temperature fields on the thermofracture behaviour of the pipeline will be demonstrated by a numerical example. (2) Thermomechanical creep fracture of structures: recent developments, including those of the author's own work, on cyclic creep-fracture using damage theory will be presented. Long “hold” and “dwell” times, which occur in the actual operations of nuclear power plant components have been shown to have a significant effect on the overall creep-fracture behaviour of the material. Constitutive laws, which include most of these effects, have been incorporated into the existing TEPSAC code for the prediction of crack growth in solids under cyclic creep loadings. The effectiveness of using the damage parameters as fracture criteria, and the presence of plastic deformation in the overall results will be assessed.
Mathematical models of endocrine systems

There is proposed a generalized mathematical model of endocrine systems, consisting of a set of differential equations which describe a chain of chemical reactions. The product of each reaction stimulates or inhibits some other reaction in the chain except possibly the last, which may or may not influence the system. At least one reaction must be independent and able to proceed without stimulation or inhibition by the products of other reactions.
Incidence and outcomes of cytomegalovirus in pancreas transplantation with steroid-free immunosuppression

Cytomegalovirus (CMV) is a common opportunistic infection encountered after pancreas transplantation. The records of 407 pancreas transplant recipients (226 simultaneous pancreas and kidney transplant (SPK), 101 pancreas transplant after kidney (PAK), and 97 pancreas transplants alone [PTA]) performed at a single center with at least 1-yr follow-up were reviewed. Immunosuppression included rabbit antithymocyte globulin induction, steroid withdrawal, and maintenance therapy of tacrolimus and sirolimus (± mycophenolate). In addition, PTA recipients received a single dose of rituximab. All recipients received valganciclovir prophylaxis. Donor (D)+/recipient (R)- recipients received 6 months of prophylaxis; all others received 3 months. The overall CMV infection rate was 12%. The cumulative incidences of CMV infection at 3, 6, 9, and 12 months after transplant were 0.25%, 3%, 7%, and 8%, respectively. CMV infection rates were 20.2% in the D+/R- group, 16.5% in the D+/R+ group, 5.0% in the D-/R+ group, and 2.8% in the D-/R- group. Infections were less common in SPK recipients. Most infections developed at least 3 months post-transplant, and 24% demonstrated tissue-invasive disease. Immunosuppression was NOT reduced in 72% of patients with infections. Ganciclovir-resistant CMV occurred in four patients. No patients died or lost their allografts due to CMV-related infection; one graft was lost due to chronic rejection associated with a reduction in immunosuppression. In many cases, CMV infections may be treated in pancreas transplant recipients without necessarily reducing immunosuppression.
Did the Toba volcanic eruption of 74 ka B.P. produce widespread glaciation

[1] It has been suggested that the Toba volcanic eruption, approximately 74 ka B.P., was responsible for the extended cooling period and ice sheet advance immediately following it, but previous climate model simulations, using 100 times the amount of aerosols produced by the 1991 Mount Pinatubo eruption, have been unable to produce such a prolonged climate response. Here we conduct six additional climate model simulations with two different climate models, the National Center for Atmospheric Research Community Climate System Model 3.0 (CCSM3.0) and National Aeronautics and Space Administration Goddard Institute for Space Studies ModelE, in two different versions, to investigate additional mechanisms that may have enhanced and extended the forcing and response from such a large supervolcanic eruption. With CCSM3.0 we include a dynamic vegetation model to explicitly calculate the feedback of vegetation death on surface fluxes in response to the large initial reduction in transmitted light, precipitation, and temperature. With ModelE we explicitly calculate the effects of an eruption on stratospheric water vapor and model stratospheric chemistry feedbacks that might delay the conversion of SO 2 into sulfate aerosols and prolong the lifetime and radiative forcing of the stratospheric aerosol cloud. To span the uncertainty in the amount of stratospheric injection of SO 2 , with CCSM3.0 we used 100 times the Pinatubo injection, and with ModelE we used 33, 100, 300, and 900 times the Pinatubo injection without interactive chemistry, and 300 times Pinatubo with interactive chemistry. Starting from a roughly present-day seasonal cycle of insolation, CO 2 concentration, and vegetation, or with 6 ka B.P. conditions for CCSM3.0, none of the runs initiates glaciation. The CCSM3.0 run produced a maximum global cooling of 10 K and ModelE runs produced 8-17 K of cooling within the first years of the simulation, depending on the injection, but in all cases, the climate recovers over a few decades. Nevertheless, the "volcanic winter" following a supervolcano eruption of the size of Toba today would have devastating consequences for humanity and global ecosystems. These simulations support the theory that the Toba eruption indeed may have contributed to a genetic bottleneck.
The Development of Curricular Guidelines for Introductory Microbiology that Focus on Understanding

The number of students who leave majors in science, technology, engineering, and mathematics (STEM) due to a perception that courses are poorly taught is evidence that education reform in STEM is overdue. Despite decades of research that argues for student-centered teaching approaches, most introductory STEM courses are still taught in the large lecture format, focusing on rote memorization. While individual efforts in STEM educational reform are important, solutions will most certainly need to include institutional and cultural change. In biology, numerous national reports have called for educational reform to better prepare future scientists. We describe here a new, concept-based curriculum for Introductory Microbiology courses, designed to promote deep understanding of core concepts. Supported by the American Society for Microbiology (ASM) and based on the overarching concepts and competencies presented in the AAAS/NSF report Vision and Change in Undergraduate Biology Education: A Call to Action, we hope it will empower instructors to adapt student-centered approaches so that students in Introductory Microbiology courses can leave the course with a core set of enduring understandings of microbiology.
Geometric Prequantization on the Spin Bundle Based on N-Symplectic Geometry: The Dirac Equation

We present preliminary results for a prequantization procedure that leads in a natural way to the Dirac equation. The starting point is the recently introducedn-symplectic geometry on the bundle of linear framesLM of ann-dimensional manifoldM in which the ℝn-valued soldering 1-formθ onLM plays the role of then-symplectic potential. On a 4-dimensional spacetime manifold we consider the tensorial ℝ4⊗ℝ4valued functionĝ onLM determined by the spacetime metric tensor g as the Hamiltonian for free observers and determine the associated ℝ4-valued Hamiltonian vector field\(\hat X_{\hat g} = \hat X_{\hat g}^i \otimes r_i \), Integration” of theXĝi yields the dynamics of free observers on spacetime, namely parallel transport of linear frames along spacetime geodesies. In order to obtain a vector field on the spin bundleSM which is a lift of\(\hat X_{\hat g} \) and which is induced by a vector field\(\hat X_{\hat g} \) for an appropriate mapping\(\hat g\), it is useful to define a prolongation Open image in new window of some bundleLoM of oriented frames ofM. IfGL+(4, ℝ) denotes the identity component ofGL(4, ℝ), thenGL+(4, ℝ) is the structure group ofLoM and its double cover Open image in new window is the structure group of Open image in new window . We show that the lift\(\tilde \theta \) ofθ onLoM to Open image in new window induces a natural 4-symplectic potential on Open image in new window . If\(\tilde g\) is the lift of g to Open image in new window , then we find the ℝ4-valued Hamiltonian vector field\(X_{\hat g}^i \) on Open image in new window determined by\(\tilde g\) and show that the vector fieldsXgi on Open image in new window are tangent to the subbundleSM. “Integration” of the restriction of theXĝi toSM now yields parallel transport of spin frames and thus tetrads along spacetime geodesies of g. We consider a naive prequantization operator assignment Open image in new window acting on ℂ4-spinors in the standard representation ofSL(2, ℂ). The eigenvalue equation for the system of new Hilbert space operators yields the Dirac equation.
Equipoise: asking the right questions for clinical trial design

Randomized controlled trials (RCTs) are central to evidence-based clinical and health-policy decisions. However, RCTs highlight the tension between the therapeutic obligations of the physician and the scientific obligations of the investigator. Clinical equipoise, defined as honest professional disagreement among expert clinicians about the preferred treatment, is often cited as the solution to this RCT dilemma. Nevertheless, there are numerous practical and conceptual problems with the notion of equipoise. These problems include its mistaken imposition of therapeutic norms on the scientific enterprise of research, the difficulty of knowing when a state of equipoise exists, the susceptibility of expert judgment to bias and weak evidence, and its inability to support evidence necessary for health-policy decisions. An alternate approach to risk-benefit assessment that is congruent with the scientific purpose of RCTs can better guide ethical evaluation of these trials, as discussed in this Perspective.
An Empirical Explanation of the Cornsweet Effect

A long-standing puzzle in vision is the assignment of illusory brightness values to visual territories based on the characteristics of their edges (the Craik–O’Brien–Cornsweet effect). Here we show that the perception of the equiluminant territories flanking the Cornsweet edge varies according to whether these regions are more likely to be similarly illuminated surfaces having the same material properties or unequally illuminated surfaces with different properties. Thus, if the likelihood is increased that these territories are surfaces with similar reflectance properties under the same illuminant, the Craik–O’Brien–Cornsweet effect is diminished; conversely, if the likelihood is increased that the adjoining territories are differently reflective surfaces receiving different amounts of illumination, the effect is enhanced. These findings indicate that the Craik–O’Brien–Cornsweet effect is determined by the relative probabilities of the possible sources of the luminance profiles in the stimulus.
Data-triggered threads: Eliminating redundant computation

This paper introduces the concept of data-triggered threads. Unlike threads in parallel programs in conventional programming models, these threads are initiated on a change to a memory location. This enables increased parallelism and the elimination of redundant, unnecessary computation. This paper focuses primarily on the latter. It is shown that 78% of all loads fetch redundant data, leading to a high incidence of redundant computation. By expressing computation through data-triggered threads, that computation is executed once when the data changes, and is skipped whenever the data does not change. The set of C SPEC benchmarks show performance speedup of up to 5.9X, and averaging 46%.
Scheduling a Make-To-Stock Queue: Index Policies and Hedging Points

A single machine produces several different classes of items in a make-to-stock mode. We consider the problem of scheduling the machine to regulate finished goods inventory, minimizing holding and backorder, or holding and lost sales costs. Demands are Poisson, service times are exponentially distributed, and there are no delays or costs associated with switching products. A scheduling policy dictates whether the machine is idle or busy and specifies the job class to serve in the latter case. Since the optimal solution can be numerically computed only for problems with several products, our goal is to develop effective policies that are computationally tractable for a large number of products. We develop index policies to decide which class to produce, including Whittle's "restless bandit" index, which possesses a certain asymptotic optimality. Several idleness policies are derived, and the best policy is obtained from a heavy traffic diffusion approximation. Nine sample problems are considered in a numerical study, and the average suboptimality of the best policy is less than 3%.
Affective and Behavioral Components of Shyness

With much of their research focused on mundane behavior, social and personality psychologists often borrow terms from everyday language, such as attitude, trait, aggression, and consciousness. Unfortunately, we are often remiss in explicitly defining our specialized uses of these ordinary sorts of words, especially in the early stages of research on a topic. And, even when writers clearly define their terms, they often adopt different connotations of the everyday definitions. Only after realizing that the multiplicity of implicit and explicit definitions has led to confusion and miscommunication have researchers typically paused to address conceptual issues.
Leprosy: Cause, Transmission, and a New Theory of Pathogenesis

Leprosy is generally accepted as being caused by Mycobacterium leprae, an acid-fast organism often present in great numbers in certain forms of leprosy. However, it has not been possible to confirm with scientifically acceptable evidence that this entity is the cause of leprosy; laboratory cultivation, an essential factor in the proof, has not been accomplished with the acid-fast bodies seen in leprotic tissue. The mechanisms of transmission of the disease also remain conjectural; prolonged, close contact and transmission by nasal droplet have both been proposed, and, while the latter fits the pattern of disease, both remain unproved. It is proposed that the causative agent of leprosy is not a difficult-to-transmit agent but, rather, an organism that has evolved a highly efficient state of parasitism in stable types of populations and that everyone in the population harbors the leprosy parasite at some time. The majority of the population incubate subclinical infections at various levels; clinical leprosy arises from within the pool of subclinical infection in the endemic population rather than by transmission from an index case. A theory of complete infection of endemic populations is consistent with the rate of development and distribution of positive lepromin reactions among healthy persons in endemic regions and provides an explanation for the difficulty in controlling leprosy in endemic populations by isolation of patients or by therapy for clinical cases.
Biosynthesis of S-(4-ethylamino-6-isopropylamino- 2-s-triazino) glutathione: Partial purification and properties of a glutathione S-transferase from corn☆

Abstract A soluble glutathione S-transferase from corn leaves was purified 7·6-fold by differential centrifugation, ammonium sulfate fractionation and gel filtration. Active enzyme preparations were also isolated from leaves of sorghum, sugarcane, Johnson grass and Sudan grass. The enzyme catalyzed the conjugation of several substituted 2-chloro-s-triazine herbicides with reduced glutathione. The formation of 1 mole of chloride ion for every mole of glutathione conjugate produced was demonstrated with 14C and 36Cl-labeled 2-chloro- 4-ethylamino-6-isopropylamino-s-triazine. A rapid ion exchange assay system for following the rate of 14C-labeled s-triazine conjugate formation was developed. The pH optimum for 2-chloro-4-ethylamino-6- isopropylamino-s-triazine conjugate formation was between 6·6 and 6·8. Enzyme specificity for reduced glutathione was demonstrated. Specificity and inhibition studies with substituted s-triazines indicated that a chlorine atom in the 2-position and N-alkyl side-chains in the 4 and 6 positions were required for enzyme activity. The apparent Km values for 2-chloro-4-ethylamino-6-isopropylamino-s-triazine and reduced glutathione were 3·7 × 10−5 M and 2·4 × 10−3 M, respectively. Inhibition studies demonstrated a competitive inhibition with 2-methylmercapto-4,6-bis-isopropylamino-s-triazine (Ki = 2·8 × 10−5 M) and with sulfobromophthalein (Ki = 2·7 × 10−5 M). Since this appears to be the first report of glutathione S-transferase activity in plants, the similarities and differences between the corn leaf enzyme and previously reported animal glutathione S-transferase systems were discussed. The role of this enzyme system in the rapid in vivo detoxification and selectivity of substituted 2-chloro-s-triazine herbicides was also discussed.
Construction safety research in the United States: targeting the Hispanic workforce

While it is known that Hispanics have a continuous growing participation in the construction workforce and that their fatal and non-fatal occupational injuries are higher than any other ethnic group, very little construction safety and health research has been conducted in the United States. Research that focuses on safety and health of Hispanic workers employed in the construction industry might prove beneficial in reducing injuries and promoting safe and decent workplaces for all. The purpose of this article was twofold. First, to propose a research agenda where topics such as surveillance, intervention research on high risk occupations, intervention effectiveness evaluation, design and development of effective and appropriate safety training and educational materials, and the socioeconomic impact of injuries and illnesses, are investigated among the Hispanic construction workforce. Second, to present relevant aspects inherent to this particular population that need to be incorporated into the design and development stages of any safety and health research initiative. They include the occupational, social, economic, and cultural background of Hispanic workers; use of a participatory approach, proper selection and use of translation methods; and conducting collaborative research. Certain limitations and challenges related to the availability of resources for conducting safety and health research on Hispanic workers are further discussed.
Unchanging child support orders in the face of unstable earnings

The underlying theory behind child support guidelines implies that child support orders should change when the incomes of noncustodial parents change. This paper documents changes in noncustodial fathers' earnings over a five-year period and examines the relationship between the changes in earnings and modifications in child support orders. Using detailed longitudinal administrative data from Wisconsin, the authors examine the history of orders and earnings for fathers in couples who had their first child support ordered in 2000. A substantial proportion of fathers experience large changes in earnings, but relatively few of the associated child support orders are modified. Using discrete-time multinomial event history models that consider time-varying variables and control for censored observations, we find some evidence of changes in earnings being associated with changes in orders, all else equal, but the relationship is relatively weak and order changes are not proportional to earnings changes. The findings highlight the challenges and importance of developing policies that result in child support orders being more responsive to changes in fathers' incomes. © 2010 by the Association for Public Policy Analysis and Management.
The Strange Case of Dr. von Braun and Mr. Disney: Frontierland, Tomorrowland, and America’s Final Frontier

Abstract: When Disneyland opened in 1955, it featured America’s past in Frontierland and looked at America’s future in Tomorrowland. Together they represent what scholar of religion Mircea Eliade called a “religious nostalgia” for a mythic past; in this case, a nostalgia for the western frontier. The conjoining of space exploration with the historical frontier solidified space as America’s new frontier in the popular imagination and a sense of being called by God to explore the new frontier of outer space. Disney’s Tomorrowland, in tension with Frontierland, paralleled how nostalgia for the western frontier was revived as faith in the future.
Assignment of the nucleotide binding sites and the mechanism of substrate inhibition of Escherichia coli adenylate kinase

Site-directed mutagenesis of key amino acids of adenylate kinase has been used to suggest a new model for the location of the AMP and ATP binding sites. Phe-86 and Tyr-133, which are in close contact with the inhibitor Ap5A according to previous crystallographic results, have been independently changed to tryptophan and other amino acids. The Phe-86----Trp mutant had a 3- to 6-fold change in the Km for ATP and a 44-fold increase in the Km for AMP with a simultaneous loss of AMP substrate inhibition. Thus Phe-86 is probably in close contact with bound AMP. The Tyr-133----Trp mutant showed no large effects on enzyme kinetics and suggests that the previous assignment of Ap5A occupying natural adenosine binding sites is probably incorrect. A temperature-sensitive Leu-107----Gln mutant showed a 6-fold decrease in the Km for ATP and no effect on AMP binding, suggesting that this amino acid is near the ATP binding site. Changes in the fluorescence of single tryptophan-containing mutant enzymes provided specific information about AMP and ATP binding. The fluorescence results are consistent with the kinetic studies, and also suggest that AMP substrate inhibition is caused by the formation of an abortive complex that prevents the release of product.
Hidrocarburos y compensaciones por pérdida de biodiversidad: oportunidad para el desarrollo sostenible

El Manual para la Asignacion de Compensaciones por Perdida de Biodiversidad adoptado por el Ministerio de Ambiente y Desarrollo Sostenible de Colombia representa un gran avance en la estandarizacion del calculo de cuanto, donde y como compensar aquellos impactos sobre la biodi-versidad que no pueden ser evitados, mitigados o corregidos por un proyecto licenciado. Ademas de contribuir a la mitigacion de impactos, esta nueva herramienta ofrece una oportunidad para las empresas de hidrocarburos ya que les permite anticipar las medidas de compensacion y asi planear las estrategias de implementacion y financiacion. Sin embargo, aun hay retos legales, institucionales, financieros y tecnicos para su adecuada implementacion. Estos deben superarse para que este esquema innovador de compensaciones pueda asegurar que las inversiones en compensaciones ambientales asociadas a, por ejemplo, la explotacion de hidrocarburos, contribuyan de manera efectiva a la metas de conservacion de biodiversidad y restauracion ecologica del pais
Locally ideal formulations for piecewise linear functions with indicator variables

In this paper, we consider mixed integer linear programming (MIP) formulations for piecewise linear functions (PLFs) that are evaluated when an indicator variable is turned on. We describe modifications to standard MIP formulations for PLFs with desirable theoretical properties and superior computational performance in this context.
The timing of mu activity in maize.

ABSTRACT The timing of mutator activity of Mu in maize was tested in three ways: (1) by allelism tests of phenotypically similar male-transmitted mutants, (2) by studying the clustering of phenotypically similar mutants as demonstrated by ear maps and the subsequent allelism tests of these mutants, and (3) by the induction of somatic sectors in Mu plants heterozygous for plant and endosperm marker genes. Allelism tests of phenotypically similar mutants in out-crosses of Mu plants as males established that 18.8% were allelic and that premeiotic mutants are induced. This conclusion was supported by ear maps of Mu-bearing plants, which revealed sectors of seeds that produced plants bearing phenotypically similar allelic mutants. The smallness of these sectors indicated that the premeiotic activity of Mu that gave rise to them occurred very late. The lack of visible sectors in mature sporophytic, endosperm and aleurone tissue in plants carrying Mu supports the conclusion that the mutator activity of Mu does not occur throughout the ontogeny of the plant and seems to be restricted to a time shortly before and/or during meiosis.
The Case for Multichip LSI Packaging of High-Reliability Military Electronics

Only by a judicious combination of compatible materials, technology, and "production state of the art" can ruggedness, reliability, versatility, and utilization be realized. This choice can only be achieved through high-quality system · engineering which covers the architecture, detail engineering, manufacturing, inspection, and maintenance of the product throughout its entire service life. The thesis is that the electrical, electronic, thermal, mechanical, construction, test, and rework characteristics must be given proper weight at all points in the design. This paper presents an argument for uncased packages of multichip large-scale integrated (LSI) devices as the best solution for the high-reliability system applications presented here.