cssi/SciSciGPT-SciSciNet huggingface dataset:
Determinants of withdrawal behavior: An exploratory study

Research on college persistence has typically classified nonreturnees as dropouts. Recently, this practice has been criticized by Tinto (1987) who argues that such a practice merges together different types of withdrawal behavior whose determinants may vary as a function of the particular departure behavior under consideration. This paper empirically examines whether the determinants of decisions to withdraw from the institution are similar to those affecting decisions to transfer to other institutions of higher education for the 1984 entering freshman class at a large southern institution. Results provide support for Tinto's proposition of differentiating between different types of voluntary withdrawal behavior. While institutional commitment, academic performance, finance attitudes, and student perceptions of faculty concern for student development and teaching discriminated between persisters and dropouts, only final institutional commitment and final goal commitment discriminated between persisters and transfers.
Cooperative pull and push effects on the O-O bond cleavage in acylperoxo complexes of [(Salen)MnIIIL]: ensuring formation of manganese(V) oxo species.

The acidity (pull) and the axial ligand (push) effects on the O−O bond cleavage in the [(Salen)MnIII(RCO3)L] acylperoxo complexes, with model L = none, NH3, and HCO2- (1), have been studied with B3...
Shade-grown coffee in Puerto Rico: Opportunities to preserve biodiversity while reinvigorating a struggling agricultural commodity

Shade-grown coffee contributes to biodiversity conservation and has many ecological benefits. We reviewed historical trends in coffee production and interviewed 100 coffee growers in 1999 to determine current management practices and attitudes toward the cultivation of sun and shade coffee in Puerto Rico. We discuss the outlook for the coffee industry in the 21st century and implications for biodiversity conservation, hoping lessons from Puerto Rico will apply to the international coffee industry. Throughout the 20th century, government intervention, including subsidies and technical assistance, supported coffee farming in Puerto Rico. In an effort to modernize coffee production and increase yields, the conversion from shade to sun coffee plantations was encouraged. Despite government support, the amount of land devoted to this once dominant agricultural commodity declined markedly between 1982 and 2007 (84%), due to labor shortages, low income, and catastrophic hurricanes. We found that a return to shaded plantations would be embraced by most farmers. Growers of shaded coffee were generally happier with their cultivation practices (89.3% satisfied) than growers of sun coffee (60.9% satisfied), valued biodiversity, and were willing to cultivate coffee under shade if given similar incentives to those received for farming sun coffee. The future of the coffee industry in Puerto Rico may depend on government programs that capitalize upon emerging markets for sustainably produced, shade-grown coffee. We conclude that where governments have close ties to the coffee industry, they should strive to wed economic development with the conservation of biodiversity and associated ecological services by providing support and incentives for the production of shade coffee.
Improving Image Contrast in Rocket Sprays Using Time-Gated Ballistic Imaging

Time-gated ballistic imaging is employed for imaging the near-field, optically dense region of atmospheric-pressure rocket sprays, enhancing image contrast and revealing information on spray geometry and break-up processes.
The subexponentiality of products revisited

Following the work of Cline and Samorodnitsky (Stoch. Process. Their Appl. 49(1):75–98, 1994), we reexamine the subexponentiality of the product of two random variables, X and Y, which are independent and have distributions F and G, respectively. The main result is the following: If F belongs to the class $\mathcal{A}$ [that is to say, F is subexponential and $\limsup_{x\rightarrow \infty }\overline{F}(vx)/\overline{ F}(x)<1$ holds for some v>1] and G, with G(0–)=0 and G(0)<0, satisfies $\overline{G}(ux)=o(1)\Pr \left( XY>x\right) $ for each u>0, then the distribution of XY also belongs to the class $\mathcal{A}$ .
Expanded conversations: collaborating for student learning: introduction to the special LOEX‐of‐the‐West 2002 issue

Provides an introduction to the papers of the LOEX‐of‐the‐West which concentrated on the theme of collaboration and partnership within the academic library to improve student learning. Looks at the development of information literacy and how academic libraries can use this to expand the field of student learning. Concludes that information technology has changed the face of teaching and learning, offering the opportunity to find and collaborate with new partners.
Zoledronate activates NK cells.

In this issue of Blood , Nussbaumer et al demonstrate that the bisphosphonate zoledronic acid (zoledronate), a US FDA-approved drug for the prevention of osteoporosis and treatment of bone metastases in multiple myeloma and other cancers,[1][1] can enhance IFN-γ production by IL-2–primed human
Cytogenetic and flow cytometric analysis of a pancreatoblastoma

A pancreatoblastoma from a 4-year old male was examined by flow cytometric ploidy analysis and cytogenetics. To detect differences within the tumor, the specimen was divided into four portions and sampled separately. Flow analysis revealed that each sample contained a diploid and a tetraploid population of tumor cells. These findings correlated well with the cytogenetic analysis, which also revealed differences in structural rearrangements between samples. A t(13;22)(q10;q10) was the only rearrangement found in near-diploid cells as well as one near-tetraploid line. Other common structural changes in near-tetraploid cells included t(13;13)(q10;q10), i(6p)(p10), and del(1). Chromosomes 1, 6, 13, and 22 were consistently missing from all near-tetraploid cells lines. To our knowledge, this is the first flow cytometric and cytogenetic study of a pancreatoblastoma.
THE ARTISTIC AND PROFESSIONAL DEVELOPMENT OF TEACHERS A STUDY OF TEACHERS' ATTITUDES TOWARD AND USE OF THE ARTS IN TEACHING

During the past decade, the arts have been increasingly included in professional development programs for general education teachers in the United States. Little is known, however, about teachers’ ...
A study of durability of hip implants

Abstract Total hip replacement (henceforth abbreviated THR) has become a routine surgical procedure over the past few decades. This has led to advances in understanding both the biological and the mechanistic aspects of hip joints, which in turn has fueled the quest for the ideal implant that performs as close as possible to the real hip joint. As a result, the design of hip implants is still very much evolving, which naturally requires evaluation of new ideas and designs from a durability point of view. The work presented here can be placed within this broader context. The mechanical response of both two-dimensional and three-dimensional (henceforth abbreviated 2D and 3D, respectively) finite element (henceforth abbreviated FE) models of the hip implant, including the femoral ball, have been studied for a single stance phase of gait (defined later). The influences of (i) variations in the femoral ball diameter, (ii) the nature of the contact interactions between the femoral ball and the stem, (iii) the boundary conditions on the stem, and (iv) the loading conditions on the femoral ball, on the stress distribution in the implant stem have been analyzed. In particular, the effects of the size of the femoral ball on the stress/deformation state in the implant was investigated, in order to assess whether a larger femoral ball size has an adverse effect on its durability. The accuracy of the simplified 2D model is evaluated by comparing the results with those obtained from the 3D model. The reliability of the FE results is ensured by performing mesh convergence studies. In addition, an analytical model is developed and its predictions are compared with the 2D FE results. The study suggests that stresses in the neck region decrease, while those in the contact (between the stem and the femoral ball) region increase with increasing femoral ball size. A simple fatigue life analysis based on a set of standard empirical models suggests that the change in the femoral ball size could potentially affect the design life of the implant.
Participation in crowd systems

There is growing interest in using crowds of human workers to perform information processing tasks that are difficult for machines. At IBM, we have deployed a large internal crowdsourcing contest system for software development, which has now successfully completed thousands of tasks. Contrary to concerns of power efficiency and bandwidth in machine systems, player participation and motivation are key concerns in such crowd-based human computation systems. In this paper, we demonstrate that player participation is well-described by a power-law distribution, much like Lotka's Law of scientific productivity. We further describe a momentum-based generative model for participation that explains the observed empirical phenomenon and provide a thermodynamic interpretation, discussing what it means for a crowd system to heat up. Overall, player motivation is essential for driving participation and ensuring a reliable delivery platform; several intrinsic, extrinsic, and social motivators have been identified.
Warning odor of the North American porcupine (Erethizon dorsatum)

Volatile compounds in the lipid coating of the lower-back quills of the North American porcupine,Erethizon dorsatum, were collected using headspace trapping on Tenax and analyzed by gas chromatography–mass spectrometry (GC-MS), GC with organoleptic detection, and GC with a chiral stationary phase. Over 50 components were isolated, primarily oxygenated aliphatics, lactones, and isoprenoids. The most abundant constituent was tetradecyl acetate, which does not contribute significantly to the odor of the quill lipids. GC with a wide-bore capillary column and a human nose as detector was used to determine the retention time of the peak with the characteristic porcupine odor. Comparison of this organoleptic chromatogram with those obtained with a flame ionization detector and GC-MS showed the compound to be a δ-decalactone. The racemic mixture of this optically active substance does not possess the unique odor. Resolution of the enantiomers of δ-decalactone by GC with a chiral cyclodextrin phase shows that the isomer possessing the characteristic porcupine odor is the(R)-δ-decalactone. We suggest the biological function of this compound is to serve as a warning odor, which, in conjunction with an initial quill strike, produces a conditioned aversion in potential predators.
Neurological disorders associated with cassava diet: a review of putative etiological mechanisms

Tropical ataxic neuropathy (TAN) and epidemic spastic paraparesis (konzo) are two neurological disorders associated with the consumption of cassava (Manihot esculenta) in several African countries. TAN is characterized by sensory polyneuropathy, sensory ataxia, bilateral optic atrophy and bilateral sensori-neural deafness. It occurs in elderly individuals subsisting on a monotonous cassava diet with minimal protein supplementation. Konzo is a syndrome of symmetrical spastic paraparesis with a predilection for children and young women and invariably associated with consumption of inadequately processed bitter cassava roots with minimal protein supplementation. Despite numerous epidemiological, clinical and biochemical studies aimed at elucidating the etiological mechanisms of these disorders, their etiologies remain unknown, and there is no known treatment. The diseases continue to be prevalent in endemic areas, causing significant disability and increased mortality. A fresh appraisal of the putative etiologic mechanisms proposed for these intriguing and enigmatic syndromes is presented in this paper. Evidences against a causal role for cyanide intoxication are discussed, and evidences implicating thiamine deficiency as a unifying etiological mechanism for these neurological syndromes are presented. It is concluded that urgent research is needed to evaluate thiamine status and implement a therapeutic trial of thiamine in these debilitating neurological disorders.
An Exploration of the Meaning and Practice of Special Education in the Context of Full Inclusion of Students with Learning Disabilities

In the two decades since the implementation of P.L. 94-142, great strides have been made in the provision of free, appropriate, and publicly funded special education services to students with disabilities. P.L. 94-142 established the "zero reject" principle in public education and profoundly influenced the levels of educational opportunity made available to previously unserved students. But it is the Least Restrictive Appropriate Placement provision (LRA, or LRE, as it is more commonly known) (Turnbull, 1986) that has truly revolutionized schooling for students with disabilities, even those with mild to moderate disabilities already served by the public schools at the time the Education of the Handicapped Act (EHA) was passed. The LRE provision of the Act stipulates that "special classes, separate schooling or other removal of handicapped children from the regular education environment will occur only when the nature or severity of a child's handicap is such that education in regular classes with the use of supplemental aids and services cannot be achieved satisfactorily" (Turnbull, 1986, p. 134). One response to this provision has been the movement toward more integrated educational programs for students with disabilities. This movement is not reflected in the statistical summaries published in the annual reports to Congress because the categories into which data are summarized—general class and resource room—are too broad to reflect what is happening. Anyone who reads the journals, attends professional meetings, or works in schools, however, has witnessed a significant increase in the use of administrative arrangements in which the education of students with disabilities is a shared responsibility between general and special education teachers, as called for by Will (1986) in her launching of the Regular Education Initiative. The movement toward integration appears at a time when there is a growing concern among educators, researchers, funding and regulatory agency officials, and the general public that education in the United States is not meeting the needs of a great number of children and youth. Evidence sparking this concern seems to be all around us, reported in scientific literature and in the popular press, and has spurred a massive restructuring effort and the National Goals 2000 movement (U.S. Department of Education, 1991). At the same time, there have been growing criticisms of Chapter 1, a large-scale pull-out education program aimed at students educationally at risk. The Title 1/
Enhancement of persistent sodium current by internal fluorescence in isolated hippocampal neurons

Abstract Following up on an earlier chance observation, voltage-dependent whole-cell currents were recorded from isolated hippocampal neurons filled with the fluorescent dyes Fluo-3 and Fura-red, that were intermittently excited by 488 nm laser light. In the absence of any ion channel blocking drugs, in most cells depolarizing voltage steps initially evoked only the ‘Hodgkin–Huxley’ type early, fast inward surge followed by sustained outward current. Over 5–20 min of intermittent electrical stimulation and laser-excited fluorescence pulses, a voltage-dependent, slowly inactivating inward current also appeared and grew, while sustained outward current diminished. When K + currents were blocked, a small persistent inward current was usually detectable immediately, and then it increased in amplitude. This current was blocked by tetrodotoxin (TTX) and it had current–voltage ( I–V ) characteristics of a persistent sodium current, I Na,P . In cells not filled with dye but illuminated by laser, and in cells with dye but not illuminated, I Na,P remained small. There was a more than 12-fold difference in the maximal amplitude of I Na,P of fluorescent compared to non-fluorescent cells. Once induced, I Na,P decreased very slowly. Fluorescence increased the duration but not the amplitude of the transient Na + current, I Na,T . With membrane potential clamped to a constant voltage, the laser-induced fluorescence did not evoke a membrane current. It is not certain whether fluorescence-induced I Na,P potentiation is related to photodynamic action.
Palaeoclimate: A southern misfit

Temperature reconstructions of the past millennium rely heavily on Northern Hemisphere data. Now a Southern Hemisphere temperature reconstruction is available and sheds light on the complexity of the interhemispheric temperature relationship.
Phase I study of 5-aza-2′-deoxycytidine in combination with valproic acid in non-small-cell lung cancer

Purpose Non-small-cell lung cancer (NSCLC) accounts for the majority of lung cancer and is the most common cause of cancer death in industrialized countries. Epigenetic modifications are observed universally during the tumorigenesis of lung cancer. The development of epigenetic-modulating agents utilizing the synergism between hypomethylating agents and histone deacetylase (HDAC) inhibitors provides a novel therapeutic approach in treating NSCLC.
Dynamics of a hypoid gear pair considering the effects of time-varying mesh parameters and backlash nonlinearity

A generalized nonlinear time-varying (NLTV) dynamic model of a hypoid gear pair with backlash nonlinearity is formulated which is also applicable to spur, helical, spiral bevel and worm gears. Firstly, the fundamental harmonic form of time-varying mesh parameters is used to study the effects of mesh parameter variations on the dynamic response, and the interactions between them and backlash nonlinearity. The analysis also examines the effects of mean load and mesh damping. Secondly, based on a three-dimensional quasi-static tooth contact analysis, a new significantly more exact time-varying mesh model is proposed, which describes the true mesh characteristics of hypoid gear pairs. The enhanced time-varying mesh model is applied to perform further dynamic analysis. Computational results reveal numerous interesting nonlinear characteristics, such as jump discontinuities, sub-harmonic and chaotic behaviors, especially for lightly loaded and lightly damped cases.
Coupling pathways for dihydroxy aromatics during coal pyrolysis and liquefaction

Abstract Studies with model-compounds and hybrid studies in which model compounds are added to coal experiments were conducted to elucidate the major pathways by which phenols can lead to cross-links during coal conversion. This effort was greatly facilitated by the application of field ionization mass spectrometry (FIMS). For 1,3-dihydroxynaphthalene, FIMS analysis showing the entire sequence of oligomeric coupling products up through pentamers at 688 Da demonstrates unequivocally that the stoichiometry and sequence of reactions at 400 °C involve an initial condensation to eliminate water, followed by an oxidative coupling eliminating the elements of H 2 . Reaction conditions were varied to determine the effect of neutral and basic hydroaromatic solvents, non-donor aromatic solvents, reactor surfaces, metal-oxide additives, and gas atmosphere. Resorcinol (1,3-dihydroxybenzene) couples in a similar manner, but analyzable products are difficult to intercept; evidently the initial coupling products are far more reactive toward coupling than is the starting material. Catechol (1,2-dihydroxybenzene) undergoes self-coupling at a slightly slower rate than resorcinol, while 1,4-dihydroxynaphthalene undergoes dehydroxylation in donor solvents at a rate fast enough to largely block rapid self-coupling of the dihydroxy aromatic. Hybrid experiments with a subbituminous coal (Wyodak) and these Ar(OH) 2 show that the coal possesses structures that couple far more rapidly with Ar(OH) 2 than the latter do with themselves. Simple phenols inhibit the coupling, but the amine hydroaromatic, tetrahydroquinoline, has no special inhibiting effect, except that it itself tends to couple with Ar(OH) 2 .
Dendrimer-like DNA-based fluorescence nanobarcodes

A major challenge in clinical diagnostics and environmental analysis is the difficulty in rapid and sensitive detection of multiple target molecules simultaneously (i.e., multiplexed detections). Our group has designed and synthesized a dendrimer-like DNA (DL-DNA) that is multivalent and anisotropic; using this unique DNA structure, we have developed a fluorescence-tagged nanobarcode system for multiplex detection. This nanobarcode system allows the rapid and sensitive detection of multiple pathogens simultaneously using the ratios of two different fluorescent dyes, green and red, with which different DL-DNAs are labeled. The key step of our nanobarcode model lies in the monodisperse preparation of DL-DNA. Two methods, solution phase and solid phase, are presented here. With slight modifications, this platform technology can also be extended to the multiplexed detection of RNA and proteins. This protocol can be completed in 2-5 d.
Synthesis of 2- and 2,5-substituted benzoxazoles and benzothiazoles

Abstract A number of 2- and 2,5-perfluoroalkyl and perfluoroalkylether substituted benzoxazoles and benzothiazoles have been prepared. Their relative hydrolytic stability has been examined. In all cases the benzothiazoles were more stable that the benzoxazoles. Substituents in the 2-position offering steric hindrance improve hydrolytic stability.
Agrobacterium-mediated transformation of Arabidopsis thaliana using the floral dip method

Collective efforts of several laboratories in the past two decades have resulted in the development of various methods for Agrobacterium tumefaciens-mediated transformation of Arabidopsis thaliana. Among these, the floral dip method is the most facile protocol and widely used for producing transgenic Arabidopsis plants. In this method, transformation of female gametes is accomplished by simply dipping developing Arabidopsis inflorescences for a few seconds into a 5% sucrose solution containing 0.01-0.05% (vol/vol) Silwet L-77 and resuspended Agrobacterium cells carrying the genes to be transferred. Treated plants are allowed to set seed which are then plated on a selective medium to screen for transformants. A transformation frequency of at least 1% can be routinely obtained and a minimum of several hundred independent transgenic lines generated from just two pots of infiltrated plants (20-30 plants per pot) within 2-3 months. Here, we describe the protocol routinely used in our laboratory for the floral dip method for Arabidopsis transformation. Transgenic Arabidopsis plants can be obtained in approximately 3 months.
Structural Insights into the Assembly of Large Oligomeric Signalosomes in the Toll-Like Receptor–Interleukin-1 Receptor Superfamily

Innate immunity and inflammation constitute the initial responses to injury or infection. Toll-like receptors (TLRs) participate in the recognition of invading viruses and microorganisms by recognizing molecules that are either not present or uncommon in the host cell, known as pathogen-associated molecular patterns (PAMPs). The potent proinflammatory cytokine interleukin-1β (IL-1β) is recognized by IL-1 receptor I (IL-1RI) and the co-receptor IL-1RAcP. Upon recognition of their cognate ligand, these receptors initiate a shared cytosolic signaling cascade. Structural studies have begun to reveal that these signaling cascades coalesce into large oligomeric signaling complexes or “signalosomes” for signal propagation. Through phosphorylation and ubiquitination reactions, this signaling results in the activation of the inhibitor of nuclear factor κB (NF-κB) kinase (IKK), which then phosphorylates the NF-κB inhibitor IκB, promoting its degradation. Degradation of IκB enables the transcription factor NF-κB to translocate to the nucleus and promote the expression of genes whose products are involved in innate and adaptive immunity, inflammation, cell survival, and proliferation.
A local model for the prediction of rain-rate statistics for rain-attenuation models

A new local model for the prediction of rain-rate statistics is presented. Rain-rate statistics are needed for rain-attenuation and rain-interference prediction models. The new model uses 30-year or longer climate data sets to provide parameters for a closed-form rain-rate probability distribution model. The required climate data are available for the USA and its territories. The model provides for the prediction of annual and monthly distributions and for the expected year-to-year variations in these distributions. The model was tested against empirical rain-rate distributions obtained from long term (five or more year) observation programs in the USA and Canada. It provides the only model available for predicting monthly or seasonal probability distributions. It provides a solution to the worst month distribution estimation problem because distributions may be predicted for each of the months in a year and the worst one is then readily apparent. The model provides monthly and annual distribution predictions that match the observed distributions within the expected uncertainty produced by the intrinsic interannual variations in rain occurrence.
Two rare variations, D478N and D478E, that occur at the same amino acid residue in nicotinic acetylcholine receptor (nAChR) α2 subunit influence nAChR function

Abstract There occur two rare variations, Asp(D)478Asn(N) and Asp(D)478Glu(E), in the putative cytoplasmic amphipathic α-helices of human nicotinic acetylcholine receptor (nAChR) α2 subunit as a result of mutation in the 1st (G → A: rs141072985) and 3rd (C → A: rs56344740) nucleotide of its 478th triplet codon ( G A C ). We assessed the effects of these two variations on the function of α2β2- and α2β4-nAChRs as they could alter the electronegativity and/or the structure of the cytoplasmic ‘portals’ (framed by subunit amphipathic α-helices) necessary for obligate ion permeation from extracellular space to cytoplasm. We injected decreasing ratio of subunit cRNAs (α:β; 10:1, 1:1 and 1:10) into Xenopus oocytes to express putative low-sensitivity (LS; 10:1), intermediate-sensitivity (IS; 1:1) and high sensitivity (HS; 1:10) isoforms of wild type and variant α2β2- and α2β4-nAChRs. Two-electrode voltage clamp analyses indicate that the agonist (ACh or nicotine) induced peak current responses ( I max ) of α2β2-nAChR isoforms and those of α2β4-nAChR isoforms are increased (1.3–4.7-fold) as a result of D478E variation. The α2 subunit D478N variation only increases the I max of IS (∼2-fold) or HS (1.4–2.1-fold) α2β2-nAChRs. Concentration–response curves constructed indicate no effect on agonist sensitivities of LS and HS isoforms of α2β2- or α2β4-nAChRs as a result of either variation in α2 subunit. Between the two variant nAChRs, α2(D478E)*-nAChR isoforms generally yield higher I max than those of respective α2(D478N)*-nAChR isoforms. These effects could be attributed to alteration in cytoplasmic ‘portals’ and/or ion permeation through it owing to change in amino acid electronegativity (D → N) and side chain length (D → E) in nAChR α2 subunit.
A Neutrophil-Derived Anti-Infective Molecule: Bactericidal/Permeability-Increasing Protein

Effective host defense against microbial invasion requires an innate immune system whose response is both rapid and independent of prior exposure (25). The neutrophil is a central cellular effector of the innate immune system whose importance to host defense is manifest in the increased frequency and severity of infections in patients who have defects in neutrophil quantity or quality. The mechanisms by which neutrophils exert their antimicrobial activity have been under investigation since the seminal work of Eli Metchnikoff, who demonstrated the phagocytic activity of these cells at the beginning of the 20th century. Activated neutrophils increase oxygen consumption during inflammatory responses in what has been termed the “respiratory burst,” reflecting assembly of a multicomponent neutrophil oxidase which transfers electrons to molecular oxygen, forming toxic radicals (6). Defects in the phagocyte oxidase proteins underlie chronic granulomatous disease (CGD), which is characterized by increased frequency of infections with certain bacterial and fungal pathogens (38). Nitric oxide is another small, readily diffusible antimicrobial mediator generated by activated neutrophils (54). Over the past two decades, there has been increasing recognition of oxygen-independent killing mechanisms relating to the following observations: (i) neutrophils from CGD patients are capable of killing a variety of microorganisms (52), (ii) normal neutrophils deprived of oxygen in vitro are also able to efficiently kill certain bacterial pathogens (52), (iii) crude acid extracts of neutrophils possess direct microbicidal activity which is oxygen independent (24), and (iv) cationic proteins and peptides isolated from such extracts are able to directly kill microorganisms in vitro (29). Encouraged by these observations, investigators have made use of protein chromatography and molecular cloning in order to isolate, sequence, and define a growing number of neutrophil granule-derived antimicrobial proteins and peptides (15, 22, 23). Neutrophil protein and peptide antibiotics are deployed by degranulation either extracellularly into inflammatory fluids or intracellularly into the phagolysosome, thereby exposing microorganisms to high concentrations of these agents. The antimicrobial proteins and peptides share in common a net positive charge which contributes to electrostatic interactions with negatively charged microbial surface components. However, despite similar charges, these agents vary markedly in size and structure as well as the mechanisms and selectivities of their cytotoxic actions. Here the focus is on a remarkably selective anti-infective component of human neutrophils known as the bactericidal/permeability-increasing protein (BPI).
The Secretary Problem from the Applicant's Point of View

SummaryA 1960 “Mathematical Games” column describes the problem, now known as the Secretary Problem, which asks how someone interviewing candidates for a position should maximize the chance of hiring the best applicant. This note looks at how an applicant should respond, if they know the interviewer uses this optimal strategy. We show that all but the very top applicants have the best chance of being hired if they arrange to be the last person interviewed.
The Role of Clinical Setting and Management Approach in Metabolic Testing Among Youths and Adults Treated With Antipsychotics

Objective:This study compared metabolic screening among patients who received antipsychotic treatment at community mental health centers (CMHCs), with or without case management, and patients treated elsewhere.Methods:Rates of glucose and lipid testing among youths and adults in Missouri Medicaid (N=9,473) who received antipsychotic treatment at CMHCs, with and without case management, were evaluated. Multivariable logistic regressions determined which characteristics were independently associated with metabolic testing.Results:A total of 37.0% and 17.3% of youths and 68.7% and 34.9% of adults had glucose and lipid testing, respectively. Compared with treatment elsewhere, treatment at CMHCs, with or without case management, respectively, was associated with higher odds of glucose testing (youths, adjusted odds ratio [AOR]=1.68 and 1.89; adults, AOR=1.43 and 1.44) and lipid testing (youths, AOR=2.40 and 2.35; adults, AOR=1.97 and 1.48).Conclusions:CMHCs had higher rates of metabolic testing, possibly refle...
Structure and Parametrization of Stochastic Maps of Density Matrices

The most general evolution of the density matrix of a quantum system with a finite-dimensional state space is by stochastic maps which take a density matrix linearly into the set of density matrices. These dynamical stochastic maps form a linear convex set that may be viewed as supermatrices. The property of Hermiticity of density matrices renders an associated supermatrix Hermitian and hence diagonalizable. The positivity of the density matrix does not make the associated supermatrix positive though. If the map itself is positive, it is called completely positive and it has a simple parametrization. This is extended to all positive (not completely positive) maps. A general dynamical map that does not preserve the norm of the density matrices it acts on can be thought of as the contraction of a norm-preserving map of an extended system. The reconstruction of such extended dynamics is also given.
Independent and Exclusive Modulation of Cardiac Delayed Rectifying K+ Current by Protein Kinase C and Protein Kinase A

Abstract—Expression of minK in Xenopus oocytes results in a current similar to the cardiac slow delayed rectifying K+ (IKs) current. Modulation of the IKs current in cardiac myocytes has been studied extensively because of its role in shaping the cardiac action potential. The human and cat minK cDNA have been cloned, but their regulation by protein kinases has not been characterized. We report here on the complex modulation of human and cat IKs currents by protein kinase C (PKC) and protein kinase A (PKA). Activation of PKC by phorbol ester (100 nmol/L phorbol 12,13-didecanoate [PDD]) produces an increase in IKs current that peaks after 20 minutes and then subsequently decreases to ≈50% of the control level after 1 hour. PKA activation only produces a sustained increase in IKs current. Interestingly, premodulation by PKC prevents IKs current modulation by PKA, and PKC has no effect on IKs current after potentiation by PKA. This shows that the IKs current is modulated by PKC and PKA in a mutually exclusive...
Aquatic toxicology of Turkey Creek, Missouri, USA

Abstract At low flows, ambient toxicity (measured as a reduction in Ceriodaphnia survival) was observed in two tributaries and in the main channel of Turkey Creek. Toxicity during periods of no observable stream flow was absent in Turkey Creek upstream of these sources and reduced downstream of them and a wastewater treatment plant. During stormwater runoff, ambient toxicity increased throughout Turkey Creek, but especially at the downstream sites. Toxicity was not markedly altered at the two tributary sites where there was significant toxicity under runoff and non-runoff conditions. The toxicity from the tributaries was attributed to the presence of zinc, nickel, or cadmium as implied by a follow-up analysis of a toxicity identification evaluation (TIE), known land use, and ambient water quality data. Overall, the aquatic toxicity observed in Turkey Creek is likely due to sources in the streambed, unconsolidated urban runoff, mine tailings, or synergistic effects.
Proteasome activation by hepatitis C core protein is reversed by ethanol-induced oxidative stress.

Background & Aims: The proteasome is a major cellular proteinase. Its activity is modulated by cellular oxidants. Hepatitis C core protein and ethanol exposure both cause enhanced oxidant generation. The aim was to investigate whether core protein, by its ability to generate oxidants, alters proteasome activity and whether these alterations are further affected by ethanol exposure. Methods: These interactions were examined in Huh-7 cell lines that expressed inducible HCV core protein and/or constitutive cytochrome P450 2E1 (CYP2E1) and as purified components in a cell-free system. Chymotrypsin-like proteasome activity was measured fluorometrically. Results: Proteasome activity in core-positive 191-20 cells was 20% higher than that in core-negative cells and was enhanced 3-fold in CYP2E1-expressing L14 cells. Exposure of core-positive cells to glutathione ethyl ester, catalase, or the CYP2E1 inhibitor diallyl sulfide partially reversed the elevation of proteasome activity in core-positive cells, whereas ethanol exposure suppressed proteasome activity. The results indicate that proteasome activity was up-regulated by low levels of core-induced oxidative stress but down-regulated by high levels of ethanol-elicited stress. These findings were partially mimicked in a cell-free system. Addition of core protein enhanced the peptidase activity of purified 20S proteasome containing the proteasome activator PA28 and was further potentiated by addition of liver mitochondrial and/or microsome fractions. However, proteasome activation was significantly attenuated when fractions were obtained from ethanol-fed animals. Conclusions: HCV core protein interacts with PA28, mitochondrial, and endoplasmic reticulum proteins to cause low levels of oxidant stress and proteasome activation, which is dampened during ethanol metabolism when oxidant generation is higher.
Effects of Forward Sales on Spot Markets: Pre-commitment Sales and Prices for Fresh Strawberries

Increasingly, agricultural markets are vertically coordinated. Often a thinning spot market coexists with coordinated transactions, raising the question of how private coordination affects the market as a whole. One of the greatest challenges when analyzing such market-level effects is obtaining information on private transactions. We utilize publicly available data to evaluate how informal contracts in the fresh strawberry market affect spot market prices using a generalized autoregressive conditional heteroskedastic in mean (GARCH-M) model. We find that these informal contracts increased spot prices, as argued by some industry members, while the effect on spot price volatility varied by production region.
Vapor-Phase Synthesis and Surface Functionalization of ZnSe Nanoparticles in a Counterflow Jet Reactor

Compound semiconductor nanocrystals (quantum dots) exhibit unique size-dependent optoelectronic properties making them attractive for a variety of applications, including ultrasensitive biological detection, high-density information storage, solar energy conversion, and photocatalysis. There is presently a great need for developing scalable techniques that allow efficient synthesis, size control, and functionalization of quantum dots, without a loss of the desirable optical properties. We report experimental results on the properties and surface modification of ZnSe nanoparticles grown by a continuous vapor-phase technique utilizing an axisymmetric counterflow jet reactor. Luminescent ZnSe nanocrystals were obtained at room temperature by reacting vapors of dimethylzinc:triethylamine adduct with hydrogen selenide, diluted in a hydrogen carrier gas. The two reactants were supplied from opposite inlets of the counterflow jet configuration and initiated particle nucleation in a region near the stagnation point of the laminar flow field. Surface modification of nanoparticles by adsorption of 1-pentanethiol was used to control the rate of particle coalescence. The counterflow jet technique can be scaled up for commercial production and is compatible with other vapor-phase processing techniques used in the microelectronics industry.
Lack of effect of short-term diazoxide administration on luteinizing hormone secretion in women with polycystic ovary syndrome

Objective To test the hypothesis that an acute reduction in circulating insulin affects LH secretion in women with polycystic ovary syndrome (PCOS). Design Prospective study in normal and PCOS women. Setting General Clinical Research Centers at the University of Virginia, the Medical College of Virginia, and the Massachusetts General Hospital. Patient(s) Six normal women and five women with PCOS. Intervention(s) Administration of diazoxide to lower circulating insulin concentrations. Main Outcome Measure(s) Characteristics of LH secretion as appraised by multiparameter deconvolution and estimation of approximate entropy. Result(s) Short-term administration of diazoxide had no effect on the secretion of LH in women with PCOS. Conclusion(s) Hyperinsulinemia resulting from insulin resistance in women with PCOS may not have a direct effect on gonadotropin secretion.
Fiber design considerations for 40 Gb/s systems

In this paper, we review the fundamental advantages and drawbacks of 40-Gb/s systems from a fiber manufacturer's perspective. Based on modeling, experimental results, and fundamental understanding, we correlate the fiber design parameters with the expected performance of long-haul systems operating at 40 Gb/s. Nonlinear penalties, dispersion tolerances, modulation formats, polarization-mode dispersion, and Raman amplification are covered. We also present the fiber features required for both metro and submarine networks at this specific data rate.
Outcomes Research: Importance to (and of) Echocardiography

Cardiovascular imaging has evolved enormously during our lifetimes. When we began our medical training, ‘‘cardiac imaging’’ was synonymous with chest x-ray, generally involving PA (postero-anterior) and lateral films and sometimes including oblique films combined with a barium swallow in order to outline the esophagus and thereby to delineate the left atrium. How times have changed! Beginning more than 55 years ago, a few investigators began to use cardiovascular ultrasound (A-mode and M-mode) to ‘‘image’’ the heart. In retrospect, initial approaches seem to have been rudimentary, involving the ability to visualize certain cardiac structures using an ‘‘ice pick’’ view from the precordium. This was certainly valuable for identifying pericardial effusion, documenting LV size and global function, and demonstrating the presence of valvular and congenital abnormalities. However, the diagnostic utility and clinical use of echocardiography took a major leap forward about 30 years ago with the advent of instruments for real-time tomographic two-dimensional echocardiography (2D echo). Subsequently, perfection of Doppler methods for imaging blood flow and measuring its velocity, development of endoscopic probes for transesophageal imaging, refinement of three-dimensional (3D) imaging using both transthoracic (TTE) and transesophageal echo (TEE) approaches, development of contrast microbubble techniques for image enhancement and for assessing shunts and perfusion, and evolution of Doppler and non-Doppler methods for measuring myocardial deformation, have made cardiovascular ultrasound imaging a robust family of diagnostic techniques useful for virtually every type of known or suspected cardiovascular disorder. While echocardiographers were busy perfecting their techniques and documenting new methods for diagnosing the presence and severity of a wide range of cardiovascular disorders, and for evaluating their progression and/or response to treatment, a number of other cardiovascular imaging techniques were also evolving. Today, cardiologists and all other healthcare providers who see patients with cardiovascular diseases (and those with symptoms suggesting cardiovascular disease) have at their disposal a range of cardiovascular imaging options including cardiovascular ultrasound, radionuclide imaging, computed tomography (CT), cardiac magnetic resonance (CMR), and positron emission tomography (PET) imaging. This is not the venue, and we are not expert enough in other imaging techniques, to compare and contrast the relative strengths and weaknesses of the different approaches to cardiovascular imaging. However, two things are quite clear: (a) a number of options exist for diagnostic eval-
Viscoelastic fluid description of bacterial biofilm material properties.

A mathematical model describing the constitutive properties of biofilms is required for predicting biofilm deformation, failure, and detachment in response to mechanical forces. Laboratory observations indicate that biofilms are viscoelastic materials. Likewise, current knowledge of biofilm internal structure suggests modeling biofilms as associated polymer viscoelastic systems. Supporting experimental results and a system of viscoelastic fluid equations with a linear Jeffreys viscoelastic stress-strain law are presented here. This system of equations is based on elements of associated polymer physics and is also consistent with presented and previous experimental results. A number of predictions can be made. One particularly interesting result is the prediction of an elastic relaxation time on the order of a few minutes-biofilm disturbances on shorter time scales produce an elastic response, biofilm disturbances on longer time scales result in viscous flow, i.e., nonreversible biofilm deformation. Although not previously recognized, evidence of this phenomenon is in fact present in recent experimental results.
Embedded capacitive displacement sensor for nanopositioning applications

The scale of nano objects requires very precise position determination. The state-of-the-art manipulators involve accurate nanometer positioning. This paper presents the design of a capacitive displacement sensor for a nanopositioning application. The challenges of designing a capacitor sensitive to nanometer movements that fits in the area of a few hundred square micrometers are described. Analysis of several different designs was carried out using commercial simulation software. Results suggest a sensing resolution of 10 nm displacement. A sensor prototype was fabricated and tested.
Implications for Physical Activity in the Population With Low Back Pain

Low back pain is consid- ered the most prevalent pain complaint affecting the general population, with a reported lifetime prevalence of up to 75%. It is a recognized societal prob- lem from both a disablement and eco- nomic perspective, with costs exceeding that of coronary artery disease, respira- tory infections, and diabetes. The tradi- tional concept of low back pain having a favorable natural history paints an overly optimistic prognosis when considering recent epidemiological data. From a prognostic perspective, more than three quarters of individuals will have a recurrence of their symptoms within a year from the initial onset, and up to 40% report a permanent reduction in activity participation. Fear of move- ment and avoidance of physical activity participation have been associated with a less than desirable prognosis, often times leading to chronicity. Although numerous interventions with often con- tradictory findings have been described for the population with low back pain, a consensus of research has implicated the resumption and pursuit of appropriate physical activity as an efficacious inter- vention. This article reviews the current evidence pertaining to physical activ- ity participation in the population with low back pain and provides recommen- dations for identifying individuals who may be at risk for chronicity resulting from fear and avoidance of activity.
Spectral preferences and the role of spatial coherence in simultaneous integration in gray treefrogs (Hyla chrysoscelis).

The perceptual analysis of acoustic scenes may often require the integration of simultaneous sounds arising from a single source. Few studies have investigated the cues that promote simultaneous integration in the context of acoustic communication in nonhuman animals. This study of Cope’s gray treefrog (Hyla chrysoscelis) examined female preferences based on spectral features of conspecific male advertisement calls to test the hypothesis that cues related to common spatial origin promote the perceptual integration of simultaneous signal elements (harmonics). The typical advertisement call comprises two harmonically related spectral peaks near 1.1 kHz and 2.2 kHz. Subjects generally exhibited preferences for calls with two spatially coherent harmonics over alternatives with just one harmonic. When given a choice between a spatially coherent call (both harmonics originating from the same speaker) and a spatially incoherent call (each harmonic from different spatially separated speakers), subjects preferentially chose the former in the same relative proportions in which it was chosen over single-harmonic alternatives. Preferences for spatially coherent calls over spatially incoherent alternatives did not appear to result from greater difficulty localizing the spatially incoherent sources. These results are consistent with the hypothesis that spatial coherence promotes perceptual integration of simultaneous signal elements in frogs.