cssi/SciSciGPT-SciSciNet huggingface dataset:
Structure and dynamics of the iron responsive element RNA: implications for binding of the RNA by iron regulatory binding proteins

The iron responsive element (IRE) is a approximately 30 nucleotide RNA hairpin that is located in the 5' untranslated region of all ferritin mRNAs and in the 3' untranslated region of all transferrin receptor mRNAs. The IREs are bound by two related IRE-binding proteins (IRPs) which help control intracellular levels of iron by regulating the expression of both ferritin and transferrin receptor genes. Multi-dimensional NMR and computational approaches were used to study the structure and dynamics of the IRE RNA in solution. The NMR data are consistent with formation of A-form helical stem regions, a one-base internal bulge and a Watson-Crick C.G base-pair between the first and fifth nucleotides in the loop. A superposition of refined structures indicates that the conserved C in the internal bulge, and three residues in the six-nucleotide hairpin loop are quite dynamic in this RNA. The structural roles of the stems, the loop and the bulge in the function of the IRE RNA and in possible interactions with the iron regulatory protein are discussed.
GLAST LAT silicon tracker

The Large Area Telescope (LAT) on the Gamma-ray Large-Area Space Telescope (GLAST) mission is designed to provide unprecedented sensitivity in the exploration of the gamma-ray sky. Gamma rays with energy above 10 MeV are detected via the pair conversion process, using a precision silicon tracker-converter and a hodoscopic CsI calorimeter. Charged cosmic rays are rejected by a tiled plastic-scintillator anti-coincidence detector. We report here on the design, prototyping, testing and expected performance of the silicon tracker-converter, which will be the largest silicon detector system in space after the GLAST launch in 2006. Specifically, we discuss the electronics system, the mechanical system, results from beam tests and a balloon flight, assembly procedures and prototyping experience, and expected performance of the tracker-converter.
Parental Status and Differential Investment in Sons and Daughters: Trivers-Willard Revisited

According to the Trivers-Willard (T-W) hypothesis there is an interaction between individual status and investment in offspring such that high-status individuals invest more in boys, and low-status individuals invest more in girls. Parental investment may be both physiological and affect the sex ratio of offspring, or it may be psychological and affect resource allocation to offspring. I test both components of the hypothesis using cumulative U.S. General Social Survey (GSS) data and find results that support T-W. Using years of education attained as an indirect measure of parental investment, I find that sons of high-status fathers attain more education than daughters and that the daughters of low-status fathers attain more education than sons. Supporting the sex ratio component of T-W, I find that high-status men have more sons.
Imaging in Chronic Traumatic Encephalopathy and Traumatic Brain Injury

Context:The diagnosis of chronic traumatic encephalopathy (CTE) can only be made pathologically, and there is no concordance of defined clinical criteria for premorbid diagnosis. The absence of established criteria and the insufficient imaging findings to detect this disease in a living athlete are of growing concern.Evidence Acquisition:The article is a review of the current literature on CTE. Databases searched include Medline, PubMed, JAMA evidence, and evidence-based medicine guidelines Cochrane Library, Hospital for Special Surgery, and Cornell Library databases.Study Design:Clinical review.Level of Evidence:Level 4.Results:Chronic traumatic encephalopathy cannot be diagnosed on imaging. Examples of imaging findings in common types of head trauma are discussed.Conclusion:Further study is necessary to correlate the clinical and imaging findings of repetitive head injuries with the pathologic diagnosis of CTE.
Farther and Farther from the Original Fifth Amendment: The Recharacterization of the Right Against Self-Incrimination as a 'Trial Right' in Chavez V. Martinez

This article argues that the Supreme Court has systematically failed to address the important questions about how the Fifth Amendment right against compelled self-incrimination should apply to the police interrogation practices that emerged during the nineteenth century, well after the framing of the Bill of Rights itself. It undertakes to explain why that failure occured, and it also argues that the Court compounded its earlier failure when it misconstrued the Fifth Amendment right as a mere trial right in Chavez v. Martinez, 538 U.S. 760 (2003). The article initially surveys the opinions in Martinez and argues that the originalist analysis in Justice Thomas's majority opinion ignored the obvious point that the right against self-incrimination is not set out among the criminal trial rights articulated in the Sixth Amendment, but rather is set out among the rights pertaining to the initiation of criminal prosecutions in the Fifth Amendment. It also points out that Justice Thomas's narrow construction of in any criminal case as though that phrase referred only to a criminal defendant's own trial conflicts with legislative history that indicates that the phrase was inserted in the Amendment merely to indicate that the right applied only to criminal but not civil matters. The article then attempts to illuminate the intended meaning of the Fifth Amendment right by reconstructing the framing-era understanding of the right and by identifying the confusion that arose during the nineteenth century between the constitutional right, which restricted government interrogations, and the late-eighteenth century evidentiary confession doctrine, announced in King v. Warrickshall (1883) (a case which was not published until after the framing), that only addressed the admissibility of confessions obtained by private persons. The article also argues that the Supreme Court initially failed to apply the constitutional right to police interrogation when that practice appeared in the mid nineteenth century because it did not yet perceive such interrogations to be governmental, and that the original understanding of the right was further obscured when a defendant's right to be silent emerged in criminal trial practice in the late nineteenth century. Thus, a constitutional right against government interrogation was transformed instead into a mere rule of admissibility of the fruits of such interrogation. In sum, the treatment of the Fifth Amendment right in Chavez v. Martinez as merely a trial right is the product of compounded misunderstandings of the Fifth Amendment right, but is far removed from the original understanding of that right.
Uncertainty and War Duration

This article argues that private information plays an important role in explaining long wars. Existing rationalist explanations of long, intensely fought wars focus on commitment problems rather than private information as the cause of such wars. Commitment-problem explanations of long wars claim that while private information can explain short wars, battles and exchanges of offers for settlement should quickly reveal private information, thereby leading to an early peace. Commitment problems, on the other hand, may take years to resolve and therefore can explain long, intense wars for unitary actors. However, while commitment problems are an important explanation for long wars, private information can endure deep into lengthy conflicts because states create new private information during wars and because states often disagree about their relative ability to bear costs rather than their relative military capabilities. I explore this argument in cases on the end of the First World War and the Iran–Iraq War.
Growth stimulation of rat colonic cells in organ culture with N-methyl-N'-nitro-N-nitrosoguanidine.

The effects of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on rat colonic mucosa were investigated in organ culture. Distal colonic mucosa separated from the muscle layers was cultured on a substrate of human fibrin foam. Exposure of colonic organ cultures to 0.1, 1.0, and 10.0 micrograms MNNG/ml of medium on a multiple discontinuous basis, e.g., every third day for 3 hr, produced significant carcinogen effects. [3H]Thymidine was incorporated throughout crypts and in surface epithelium of carcinogen-treated explants. Outgrowth of epithelioid cells into the fibrin foam matrix was observed in all treated explants 9 days after initial MNNG exposure. Control untreated cultures showed limited outgrowth. After 15 and 21 days in culture, epithelioid outgrowth was still observed in 1.0 microgram MNNG/ml-treated cultures.
Circadian variation in rat plasma zinc and rapid effect of dietary zinc deficiency.

AbstractAdult rats on a 12-hr light/dark schedule fed a complete diet exhibited a circadian variation in plasma zinc, with a sharp decline of 25% between 8 and 12 hr after the beginning of the light cycle. In rats fed a zinc-deficient diet for 24 hr, plasma zinc concentration was similar to that of controls for the first 12 hr, but continued to fall further, and was significantly lower than controls after 14 hr. When rats were fed the zinc-deficient diet beginning at 8 hr of the light cycle, their plasma zinc concentration was significantly reduced 6 hr later. The results demonstrate the rapid effect of dietary zinc deficiency.
Picosecond to Millisecond Structural Dynamics in Human Ubiquitin

Human ubiquitin has been extensively characterized using a variety of experimental and computational methods and has become an important model for studying protein dynamics. Nevertheless, it has proven difficult to characterize the microsecond time scale dynamics of this protein with atomistic resolution. Here we use an unbiased computer simulation to describe the structural dynamics of ubiquitin on the picosecond to millisecond time scale. In the simulation, ubiquitin interconverts between a small number of distinct states on the microsecond to millisecond time scale. We find that the conformations visited by free ubiquitin in solution are very similar to those found various crystal structures of ubiquitin in complex with other proteins, a finding in line with previous experimental studies. We also observe weak but statistically significant correlated motions throughout the protein, including long-range concerted movement across the entire β sheet, consistent with recent experimental observations. We expect that the detailed atomistic description of ubiquitin dynamics provided by this unbiased simulation may be useful in interpreting current and future experiments on this protein.
Combining Model Checking and Testing

Model checking and testing have a lot in common. Over the last two decades, significant progress has been made on how to broaden the scope of model checking from finite-state abstractions to actual software implementations. One way to do this consists of adapting model checking into a form of systematic testing that is applicable to industrial-size software. This chapter presents an overview of this strand of software model checking.
Thermal effects in Cs DPAL and alkali cell window damage

Experiments on power scaling of Diode Pumped Alkali Lasers (DPALs) revealed some limiting parasitic effects such as alkali cell windows and gain medium contamination and damage, output power degradation in time and others causing lasing efficiency decrease or even stop lasing1 . These problems can be connected with thermal effects, ionization, chemical interactions between the gain medium components and alkali cells materials. Study of all these and, possibly, other limiting effects and ways to mitigate them is very important for high power DPAL development. In this talk we present results of our experiments on temperature measurements in the gain medium of operating Cs DPAL at different pump power levels in the range from lasing threshold to the levels causing damage of the alkali cell windows. For precise contactless in situ temperature measurements, we used an interferometric technique, developed in our lab2 . In these experiments we demonstrated that damage of the lasing alkali cell starts in the bulk with thermal breakdown of the hydrocarbon buffer gas. The degradation processes start at definite critical temperatures of the gain medium, different for each mixture of buffer gas. At this critical temperature, the hydrocarbon and the excited alkali metal begin to react producing the characteristic black soot and, possibly, some other chemical compounds, which both harm the laser performance and significantly increase the harmful heat deposition within the laser medium. This soot, being highly absorptive, is catastrophically heated to very high temperatures that visually observed as bulk burning. This process quickly spreads to the cell windows and causes their damage. As a result, the whole cell is also contaminated with products of chemical reactions.
Dysregulated human Tyrosyl-DNA phosphodiesterase I acts as cellular toxin

// Selma M. Cuya 1 , Evan Q. Comeaux 1, 2 , Keith Wanzeck 1, 3 , Karina J. Yoon 1 , Robert C.A.M. van Waardenburg 1 1 Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294-0019, USA 2 Department of Pathology, St. Jude Children’s Research Hospital, Memphis, TN 38105-3678, USA 3 Department of Medicine, Division of Clinical Immunology & Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35294-0001, USA Correspondence to: Robert C.A.M. van Waardenburg, email: rvanwaar@uab.edu Keywords: TDP1, DNA-adducts, biochemistry, DNA topoisomerases, DNA repair Received: July 16, 2016 Accepted: November 09, 2016 Published: November 23, 2016 ABSTRACT Tyrosyl-DNA phosphodiesterase I (TDP1) hydrolyzes the drug-stabilized 3’phospho-tyrosyl bond formed between DNA topoisomerase I (TOPO1) and DNA. TDP1-mediated hydrolysis uses a nucleophilic histidine (His nuc ) and a general acid/base histidine (His gab ). A Tdp1His gab to Arg mutant identified in patients with the autosomal recessive neurodegenerative disease SCAN1 causes stabilization of the TDP1-DNA intermediate. Based on our previously reported His gab -substitutions inducing yeast toxicity (Gajewski et al. J. Mol. Biol. 415, 741-758, 2012), we propose that converting TDP1 into a cellular poison by stabilizing the covalent enzyme-DNA intermediate is a novel therapeutic strategy for cancer treatment. Here, we analyzed the toxic effects of two TDP1 catalytic mutants in HEK293 cells. Expression of human Tdp1His nuc Ala and Tdp1His gab Asn mutants results in stabilization of the covalent TDP1-DNA intermediate and induces cytotoxicity. Moreover, these mutants display reduced in vitro catalytic activity compared to wild type. Co-treatment of Tdp1 mutant with topotecan shows more than additive cytotoxicity. Overall, these results support the hypothesis that stabilization of the TDP1-DNA covalent intermediate is a potential anti-cancer therapeutic strategy.
Performance of an optical differentiation wavefront sensor based on binary pixelated transmission filters

An optical differentiation wavefront sensor based on binary pixelated transmission filters allows for accurate wavefront metrology from two measured orthogonal wavefront gradients. Numerical and experimental investigation of its performance is presented.
SMAD4 loss in colorectal cancer: Correlation with recurrence, chemoresistance, and immune infiltrate.

587Background: Few markers reliably identify colorectal cancer (CRC) patients at risk of recurrence and death. SMAD4 loss occurs in 10-20% of cases and has shown promise in identifying high-risk stage II/III patients. We examined SMAD4 status and association with clinical/pathologic features in 446 stage I-IV CRC patients at Memorial Sloan Kettering (MSK). Methods: Patients undergoing curative resection were included (1981-2010). Familial polyposis syndrome patients and those with inadequate tissue were excluded. Tissue microarrays were constructed (n=364). Immunohistochemistry for SMAD4 and mismatch repair (MMR) proteins was completed. SMAD4 nuclear stain intensity was scored (scale=0-3; 0=loss). On whole sections, MMR proteins (present or absent), tumor-infiltrating lymphocytes (TILs) and peritumoral lymphocyte aggregates (PLAs) were scored (scale=0-3). Associations between clinical/pathologic features and SMAD4 loss vs. retention were analyzed. Kaplan-Meier estimates and log-rank test were used for rec...
Rapid, enantioselective synthesis of the C1–C13 fragment of biselyngbyolide B

A rapid synthesis of the C1–C13 fragment of biselynbyolide A and B is reported. The judicious use of catalytic transformations for C–C bond formation and stereocenter generation greatly minimizes the use of protecting groups and oxidation state changes, as compared to previously reported routes to similar fragments.
Entrepreneurial Attitudes and Knowledge of Black Youth

This study investigates the attitudes towards, education in, and knowledge of entrepreneurship of black youth using results from a national survey that was administered to a random sample of youth,...
NAD+-dependent deacetylase SIRT3 in adipocytes is dispensable for maintaining normal adipose tissue mitochondrial function and whole body metabolism.

Mitochondrial dysfunction in adipose tissue is involved in the pathophysiology of obesity-induced systemic metabolic complications, such as type 2 diabetes, insulin resistance, and dyslipidemia. Ho...
Wanting It All

Growing up in the 1960s and 1970s when so many changes were happening in American society made me believe that my dreams could be fulfilled and that being a woman was no longer a barrier to the career that I wanted. I could be married and have children and have a successful career. However, along with “wanting it all” is the reality that you have to prioritize and learn to balance what is most important to you in life. This is my story of how I have managed to wear the many hats that I do: as a chemistry professor at a mid-sized, private Catholic university, as a research mentor, as a wife, daughter, sister, and friend, and as a mother.
The Pelvic Exam and Pap Smear

Although the incidence of cervical cancer has declined in the United States, it remains one of the leading causes of cancer-related death in developing countries. Despite advances in cervical cancer screening, there were an estimated 11,150 cases of invasive cervical cancer in the USA in 2007 with 3,670 women expected to die of the disease. It is important to utilize the screening methods available to detect cervical changes early.
Caregiver Perceptions of Music Therapy for Children Hospitalized for a Blood and Marrow Transplant: An Interpretivist Investigation.

BackgroundDespite pharmacological and psychosocial support, pediatric blood and marrow transplant (BMT) recipients typically experience heightened levels of somatic and psychological distress while...
Precision Flexure Mechanisms in High Speed Nanopatterning Systems

Semiconductor wafer nanolithography machines integrate nano-scale precision mechanisms with advanced optical and mechatronic modules to achieve highly controlled nanopatterning capability for fabricating advanced integrated circuits, photonics, and optoelectronic devices. The machines achieve their precision by combining the use of highly repeatable nano-resolution actuators and motion systems, and on-tool precision calibration that is typically required for assembled systems since the sub-system machining precision is inherently insufficient.
The interplay of strategic orientations and their influence on sme performance

This paper examines the role that learning orientation plays with respect to entrepreneurial orientation, market orientation, and, ultimately, the performance of small and medium-sized enterprises SMEs. Previous research indicated mixed findings in regards to the relationship of these strategic orientations and firm performance. Instead of just direct influences to performance, we examine if learning orientation is an antecedent to market and entrepreneurial orientation. We suggest that in this way, their influence to SME performance would be more accurately predicted. We argue that learning orientation reflects the overall values of the organization, whereas entrepreneurial and market orientations are more action-oriented firm behaviors. Learning orientation would likely set the stage for the requisite actions implied in market and entrepreneurial orientation. Direct effect and mediated effects hypotheses between these strategic orientations are tested on a sample of SME manufacturing firms and their performance. Findings indicate that learning and entrepreneurial orientation directly influence SME performance. However, when learning orientation and its effects are mediated by market and entrepreneurial orientation, direct effects disappear when testing this model. The study offers insight into relationships between various strategic orientations, as to how and when they might influence SME performance.
United States v. Drayton: Supreme Court Upholds Standards for Police Conduct During Bus Searches

Introduction 1066 I. Fourth Amendment Jurisprudence: Consent Searches.........1068 A. Supreme Court Establishes “Free to Leave” Test 1068 B. Florida v. Bostick: Supreme Court Upholds Constitutionality of Bus Sweeps 1069 C. A Circuit Split Arises from Florida v. Bostick 1070 II. Procedural History of United States v. Drayton 1071 III. Supreme Court Balances Fourth Amendment Rights with Law Enforcement Initiatives to Control Drug Trafficking....1072 A. Legal Debate Over the Adoption of a Per Se Rule .........1073 B. Drayton Court Upholds Stare Decisis 1074 C. Broader Impact of Drayton for Passengers of Public Transportation 1076 D. Future Implications: Legal and Practical 1077 Conclusion 1078
Factors impacting use of adjuvant therapy in lip and oral cavity squamous cell carcinoma: A NCDB analysis.

e18556Background: Two trials followed by a combined analysis of the trials in head and neck squamous cell carcinoma (SCC) established that the benefit of adjuvant chemotherapy concurrent with radia...
Technical Perspective of Concurrent Prefix Recovery: Performing CPR on a Database

Where do novel database system research results come from? In the 1970's, most systems research papers proposed mechanisms to support abstractions that were being explored for the first time, such as data translation, indexing, query optimization, high performance transactions, distributed databases, heterogeneous databases, and replicated databases. Novelty was easy to come by. These abstractions now form the core of the database systems field.
The Effect of Graft Density on the Ordering of Block Copolymer Grafted Nanoparticles

The effect of graft density and length on the ordering of spherical nanoparticles with block copolymer (BCP) grafts was investigated using a dissipative particle dynamics model with a hard nanopart...
Effective Medium Expression for the Optical Properties of Periodic Multilayer Films

We derive an expression for the normal incidence transmittance of light through a multilayer film consisting of an arbitrary number of sequential layers of two materials with different optical constants. For wavelengths large compared to the thicknesses of the two materials, da and db, the optical properties of the multilayer film are determined by a complex effective medium dielectric constant ee=eada/(da+db)+ebdb/(da+db) where ea and eb are the complex dielectric constants of the two materials. We verify the correctness of the effective medium expression by comparing the optical spectra of multilayer films predicted by this formula with numerical calculations obtained by solving the boundary value problem for all layers. After establishing the validity of the effective medium expression, we then use it to analyze optical transmittance data of multilayer films consisting of hydrogenated amorphous silicon (a-Si:H) and amorphous silicon nitride (a-SiNx:H). The optical gap Eo of the a-Si:H layers is found to increase with decreasing a-Si:H layer thickness whereas the slope B of the Tauc plot remains constant.
Market innovation and competitive advantage of telecommunication companies in Kenya

Research question. To survive, organizations must have a competitive advantage in order to stay ahead of the competition. Market innovation has remained the driving force behind most market expansions and stability in the turbulent nature of global economies. The research question for the study thus was, “do market innovations influence the competitive advantage of telecommunication companies in Kenya?” Design/Method/Approach. Using the philosophy of positivism, the study adopted an explanatory research design in testing the hypothesis. The main data collection instrument was a structured questionnaire using both physical conduct and online interactions to return 247 responses from mid and top-level managers in a total of 26 active telecommunications companies in Kenya. The study used both descriptive and inferential statistics using SPSS computer application to analyze the data. Findings. The study findings established that innovative distribution channels significantly influenced the competitive advantage of telecommunication companies in Kenya, while advertising and promotions did not have a significant influence. This led to the conclusion that market innovation has a significant influence on the competitive advantage of telecommunication companies in Kenya. Practical implications. The study recommends that telecommunication companies need to form collaborations and partnerships for establishing market distribution channels that have indicated to bring influence onto the competitive advantage of the companies. Other recommendations include a wider coverage of the East African market for the telecommunications sector. The study provides insights into new companies with an interest in the region. Originality/Value. From the results, marketing and promotions are not the only major contributing factors in the competitive advantage of telecommunication companies in Kenya; one must consider distribution channels too. Research limitations/Future Research. The study faced limitations on visiting the field during the COVID-19 pandemic period, thus encountering entry restrictions into various premises. All protocols were observed to overcome that obstacle. Some of the telecommunications companies were facing difficulties in operations and hence could not participate. Paper type. Empirical.
Pregnant women’s experiences during the COVID-19 pandemic: A mixed method exploration of prenatal depression

Risk factors associated with prenatal depression have been studied extensively, but it is unclear whether typical risks are relevant during the COVID-19 pandemic. This mixed-method study involved surveys and interviews with women in their third trimester of pregnancy to understand prevalence and correlates of prenatal depression during a pandemic event. Survey participants included 378 pregnant women in the United States with due dates between April and December 2020 who self-reported depressive symptoms using the 10-item Edinburgh Postnatal Depression Scale (EPDS). Participants were predominately white, married, and highly educated. A subset of 21 women participated in qualitative interviews. In total, 56.3% of women reported depressive symptoms consistent with clinical levels of prenatal depression. Correlates of depressive symptoms included younger age, unmarried status, lack of access to paid parental leave, feeling unsafe in current romantic relationship, fear and worry about upcoming childbirth, and change in birth plans due to the COVID-19 pandemic. In-depth interviews with participants revealed key themes around pregnant women’s experiences with fear and anxiety, mixed emotions, and grief and loss. These findings underscore the pervasive impact of the COVID-19 pandemic on women during the perinatal period, with specific implications for the care of women with prenatal depression and their families. The heightened potential for prenatal depression in the context of the COVID-19 pandemic is concerning given the potential adverse effects of maternal depression. Practitioners must work together to engage in additional assessment of risks of prenatal depression to ensure support for expecting families is readily accessible. (PsycInfo Database Record (c) 2021 APA, all rights reserved) © 2021 American Psychological Association
Classic Linear Mediation Analysis of Complex Survey Data Using Balanced Repeated Replication

Mediation analysis revealing whether an exposure affects a response via a mediator is scientifically and practically important. Applications to complex survey data from stratified multistage sampling have been technical challenges. Balanced repeated replication (BRR) is one common variance estimation method suggested for national/international complex surveys such as Tobacco Use Supplement to the Current Population Survey (TUS-CPS) and Program for International Student Assessment (PISA). Researchers working on complex survey data are commonly SAS users. To facilitate the application of mediation analysis to complex surveys, this study develops the SAS macro %MediationBRR implementing a recently proposed method that adjusts to complex sampling designs in classic linear mediation analysis and illustrates the applications using data from TUS-CPS and PISA.
Factors affecting broadleaf woody vegetation in upland pine forests managed for longleaf pine restoration

Controlling broadleaf woody plant abundance is one of the greatest challenges in longleaf pine (Pinus palustris Mill.) ecosystem restoration. Numerous factors have been associated with broadleaf woody plant abundance in longleaf pine ecosystems, including site quality, stand structure, and fire frequency and intensity, yet the way in which these factors vary and interact across a landscape is poorly understood. The goal of this study was to quantify the importance of environmental and management factors and their interactions on the abundance of hardwood tree and shrub species in upland pine forests managed for longleaf pine restoration in Fort Benning, GA. We measured understory, midstory, and overstory vegetation in 189 fixed-area plots, and we assembled descriptive plot data about soil texture classes, slope and aspect, and fire management history. We used classification and regression trees to model broadleaf woody species abundance. Regression trees identified fire return interval, soil texture, and slope as the most important factors affecting understory woody plant cover, with high mean cover occurring in areas with longer fire return intervals (i.e. less frequent fire), on fine-textured soils (sandy clay loams and sandy loams), and on slopes less than 6%. An interaction between soil texture and fire return interval was present and suggested that frequent fire was especially important in controlling understory broadleaf woody plants on fine-textured soils. A significant interaction emerged between soil texture and pine basal area as well, suggesting that the potential to release woody competitors with canopy removal was higher on fine-textured soils than on coarse-textured soils. The presence of hardwood stems in the midstory was most dependent upon time since burn. Other factors, such as the number of burns conducted during the growing season and topographic aspect, did not contribute significantly to variation in woody plant cover or density. Of the woody species encountered, sweetgum (Liquidambar styraciflua L.) was the most abundant, especially on plots with fire return intervals P2.6 years, on fine-textured soils, and at low pine basal areas (<9.4 m 2 /ha). Other species such as persimmon (Diospyros virginiana L.), winged sumac (Rhus copallinum L.), and southern red oak (Quercus falcata Michx.) were commonly encountered but at low densities. Our results demonstrate the general complexity of woody species control, but more importantly indicate site differences that could be used to prioritize prescribed fire application at the landscape scale.
Evaluation of Selected Solid Lubricating Films

An investigation was conducted to examine the friction and wear properties of bonded molybdenum disulfide (MoS2), magnetron-sputtered MoS2, ion-plated silver, ion-plated lead, magnetron-sputtered diamondlike carbon (MS DLC), and plasma-assisted, chemical-vapor-deposited DLC (PACVD DLC) films in sliding contact with 6-mm-diameter AISI 440C stainless steel balls. Unidirectional ball-on-disk sliding friction experiments were conducted with a load of 5.9 N and a sliding velocity of 0.2 m/s at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7 x 10(exp -7) Pa), humid air (relative humidity, approx. 20 percent), and dry nitrogen (relative humidity, less than 1 percent). The main criteria for judging the performance of the solid lubricating films were coefficient of friction and wear rate, which had to be less than 0.3 and on the order of 10(exp -6) cubic mm/N(dot)m or less, respectively. The bonded MoS2 and magnetron-sputtered MoS2 films met the criteria in all three environments. The ion-plated lead and silver films met the criteria only in ultrahigh vacuum but failed in humid air and in dry nitrogen. The MS DLC and PACVD DLC films met the requirements in humid air and dry nitrogen but failed in ultrahigh vacuum.
Transcription of Vesicular Stomatitis Virus

Up until 1970, it was not understood why the deproteinized genomic RNAs of positive-strand viruses such as poliovirus were infectious while those of negative-strand viruses such as vesicular stomatitis virus (VSV) were not. An explanation of this difference was obtained when Baltimore et al. (1970) incubated highly purified virions of VSV with nonionic detergent, salts, and nucleoside triphosphates and demonstrated that RNA was synthesized in vitro. There was an RNA-dependent RNA polymerase packaged in the virion! Since the RNA synthesized in vitro was complementary to the genomic RNA, it was thought to be messenger RNA (mRNA), and the enzyme responsible for its synthesis was named the “transcriptase.” It is now clear that the obligatory first biosynthetic step in the infectious cycles of negative-strand viruses is transcription. Since the host cells appear to lack enzymes capable of utilizing RNA as templates, the infecting virus particle must carry its own supply of transcriptase into the cell to initiate the viral reproductive cycle. It is generally assumed that the viral polymerase is totally or mostly coded for by viral genes.
An Approach to Processing of Lithium-Ion Batteries for the Zero-Waste Recovery of Materials

A low-temperature, low-energy method for recovering all the valuable, economically viable, components from the spent lithium-ion batteries has been developed which has allowed the determination of pathways for complete recycling of the battery. Lithium present in the electrolyte has been selectively leached from lithium-ion batteries. Leaching conditions were optimized including time, temperature, solid/liquid ratio, and stirring velocity. All the samples were analyzed using ICP-MS for chemical composition. Leaching is conducted in a flotation machine that was able to separate plastics by flotation, creating bubbles without the use of any external chemical excess reagents. The pregnant solution was concentrated with lithium to a higher amount in order for it to be precipitated, and it was shown that the solution could be concentrated by recirculation of the leach solution. The next set of experiments were composed of battery shredding, steel separation by magnets, leaching with distilled water, and sizing using wet sieving to account for all the components of the battery. Every fraction is sent to rare-earth rolls separation and eddy current separation for full recovery.
Biosynthesis of the peptidoglycan of bacterial cell walls. XII. Inhibition of cross-linking by penicillins and cephalosporins: studies in Staphylococcus aureus in vivo.

Abstract An uncross-linked monomer (nascent peptidoglycan unit) accumulates in cells of Staphylococcus aureus treated with low concentrations of penicillin G or with ampicillin, methicillin, or cephalothin. The uncross-linked monomer has been isolated, and analyses indicate that it represents a prefabricated subunit of the wall bearing both of the d-alanine residues of its pentapeptide precursor as well as an open pentaglycine chain. Pulse labeling experiments indicate that this uncross-linked unit is a direct precursor of the cross-linked peptidoglycan and that its cross-linking is inhibited by penicillin G. At high concentrations of penicillin G, wall synthesis ceases abruptly and no accumulation of the nascent peptidoglycan units is observed. These data have been obtained in support of the hypothesis that penicillins are substrate analogues of the d-alanyl-d-alanine end of the nascent peptidoglycan units and that they acylate the transpeptidase which catalyzes the cross-linking reaction. The data may also provide an explanation of the paradoxical observation that the killing rate in S. aureus by penicillin G is higher at low concentrations than at high concentrations of the antibiotic. In the presence of low concentrations a weakened wall may be formed, thus rendering the organisms more susceptible to lysis than at high concentrations of penicillin where wall synthesis abruptly ceases.
Nonparticipation or Misspecification? The Impacts of Nonparticipation on Dichotomous Choice Contingent Valuation

Dichotomous choice (or Referendum) contingent valuation surveys have become the predominate choice for valuing goods and services otherwise not valued in a standard market (nonmarket goods and services). A number of researchers have recently recommended that dichotomous choice contingent valuation studies include a follow-up question to all no responses to determine whether the no response is a result of unwillingness to pay, or nonparticipation. If the goal of the study is to investigate the impact of covariates on either mean willingness to pay or the probability of nonparticipation, simple identification of indifferent individuals will not suffice. A simulation study shows that existing econometric models designed to account for nonparticipation are extremely sensitive to misspecification bias. Accurate identification of the probability of nonparticipation is hampered by potential misspecification of the distribution of willingness to pay.
Slab window migration and terrane accretion preserved by low‐temperature thermochronology of a magmatic arc, northern Antarctic Peninsula

[1] Existing paleogeographic reconstructions indicate that the northern Antarctic Peninsula was central to several Mesozoic and Cenozoic tectonic events that have implications for ocean circulation and continental margin evolution. To evaluate the exhumational record of these processes, we collected new samples and measured fission track and (U-Th)/He cooling ages of apatite and zircon from 13 Jurassic and Cretaceous granitoids in western Graham Land between the northern tip of the peninsula and the Antarctic Circle. Apatite He data reveal distinct ages and systematic age patterns north and south of Anvers Island, near the midpoint of the study area: To the south, apatite He ages range from 16 to 8 Ma and young northward, whereas to the north they range between 65 and 24 Ma (with one exception at 11 Ma) and young southward. Thermal histories inferred from the ages and closure temperatures of multiple thermochronometers in single samples indicate distinct histories for northern and southern Graham Land. Northern sites reveal a Late Cretaceous pulse of rapid cooling (>7°C/Myr) followed by very slow cooling (∼1°C/Myr) to the Recent, whereas southern sites record either a pulse of rapid mid-Miocene cooling (∼8°C/Myr) or steady and moderate cooling (∼3°C/Myr) from the Late Cretaceous to the Recent. We interpret the Late Cretaceous rapid cooling in the northern part of the study area as a possible manifestation of terrane accretion associated with the Palmer Land event. We interpret the systematic spatial trends in apatite He ages and contrasting thermal histories along the peninsula as recording progressive Late Cenozoic northward opening of a slab window south of Anvers Island. This is consistent with a time transgressive pulse of ∼2–3 km of rock uplift and exhumation in the upper plate following ridge-trench collision, cessation of subduction, and opening of the slab window, presumably caused by increased asthenospheric upwelling beneath the overriding plate.
Climate change effects on plant biomass alter dominance patterns and community evenness in an experimental old‐field ecosystem

Atmospheric and climatic change can alter plant biomass production and plant community composition. However, we know little about how climate change-induced alterations in biomass production affect plant species composition. To better understand how climate change will alter both individual plant species and community biomass, we manipulated atmospheric [CO2], air temperature, and precipitation in a constructed old-field ecosystem. Specifically, we compared the responses of dominant and subdominant species to our climatic treatments, and explored how changes in plant dominance patterns alter community evenness over 2 years. Our study resulted in four major findings: (1) all treatments, elevated [CO2], warming, and increased precipitation increased plant community biomass and the effects were additive rather than interactive, (2) plant species differed in their response to the treatments, resulting in shifts in the proportional biomass of individual species, which altered the plant community composition; however, the plant community response was largely driven by the positive precipitation response of Lespedeza, the most dominant species in the community, (3) precipitation explained most of the variation in plant community composition among treatments, and (4) changes in precipitation caused a shift in the dominant species proportional biomass that resulted in lower community evenness in the wet relative to dry treatments. Interestingly, compositional and evenness responses of the subdominant community to the treatments did not always follow the responses of the whole plant community. Our data suggest that changes in plant dominance patterns and community evenness are an important part of community responses to climatic change, and generally, that such compositional shifts can alter ecosystem biomass production and nutrient inputs.
Electron transport in nanoscale bipolar transistors

As base widths are reduced to tens of nanometers in modern bipolar transistors, current transport becomes quasi-ballistic. Classical transport models do not capture transport at this scale. We report the development of a new one-dimensional bipolar transistor simulator - nanoBJT, to study electron transport in nanoscale transistors. The simulator incorporates a variety of carrier transport models, and solves these self-consistently with Poisson's equation. The resulting data demonstrate the limitations of the drift-diffusion and the energy transport models. Directions for future work are proposed.
Putaminal hemorrhage : clinical-computed tomographic correlations

Ninety-two percent of 100 patients with putaminal hemorrhage were hypertensive. Of the eight normotensive patients, seven were substance abusers or had bilateral putaminal hemorrhages. The one other normotensive patient was less than 40 years old. The 100 hemorrhages had the following locations: 1. medial putaminal (17 cases; six were normotensive and less than 40 years old and five were substance abusers); 2. lateral putaminal extending through the external capsule (eleven cases); 3. putaminal-capsular and subcortical white matter (32 cases); 4. putaminal cerebral hemispheric (19 cases); 5. putaminal-thalamic (19 cases); 6. bilateral (two cases). A disproportionate number of black patients suffered hematoma extension to the cerebral hemispheres or thalamus (46%) compared to Caucasians (23%). Overall mortality was 20% (17 blacks and three Caucasians) and occurred in patients with hematoma extension to the thalamus or cerebral hemispheres. Contrast-enhanced CT was performed in all 100 patients and provided no additional diagnostic yield. This indicates limited use for enhanced CT in hypertensive patients with putaminal hemorrhage who have a characteristic appearance of the acute hemorrhage on the nonenhanced CT.
The Role of Mechanical Forces in the Initiation and Progression of Osteoarthritis

Taken together, these recent advances in understanding of how mechanical forces cause loss of articular cartilage including identification of mechanically induced mediators of cartilage loss and of how changing joint loading can promote joint remodeling provide the basis for new biologic and mechanical approaches to the prevention and treatment of OA.
Fatigue Strength of Trip Steels.

Abstract : Comparison of the S-N curves of warm-extruded TRIP steels, heat treated to give two stabilities with respect to deformation-induced martensitic transformation during testing, reveals a beneficial effect of the transformation on fatigue behavior under stress control conditions. The proportionality of fatigue strength to ultimate tensile strength is maintained to higher strength levels relative to other steels. For a stress ratio of R = 0.1, a fatigue strength at 10 to the seventh power cycles of 180 ksi (1,240 MPa) is obtained. (Author)
Thermal sensitivity of growth rate in hatchling Sceloporus lizards: environmental, behavioral and genetic aspects.

To investigate the physiological, behavioral, and genetic contributions to growth rate, we studied the thermal sensitivity of growth rate in hatchlings of the iguanid lizards Sceloporus occidentalis and S. graciosus in the laboratory. We used a cycling thermal regime patterned after thermal environments found in nature. Growth rates increased with duration of access to radiant heat. Thus, variation in the thermal environment can cause phenotypic variation in growth rate and hence body size. The two species differed in both the magnitude and thermal sensitivity of growth rate, and these differences were associated with differences in behavioral thermoregulation. Thus, growth is determined interactively by both behavior and physiology. We found evidence of among-family variation in the growth rates of S. occidentalis, suggesting that growth rate has the genetic potential to evolve. In S. occidentalis, both growth rate and egg size affected body size of hatchlings at several weeks of age. In turn, hatchling size may affect fitness: for example, larger S. occidentalis hatchlings had higher sprint speeds and may therefore be more adept at capturing prey or evading predators. Our results demonstrate that growth rate has genetic, behavioral, and physiological components, and that the resulting effects on body size may have important consequences for ecological performance e.g., sprint speed.
Planforms in Thermal Convection With Internal Heat Sources at Large Rayleigh and Prandtl Numbers

Laboratory experiments are used to examine the effects of large amounts of internal heat generation on Rayleigh-Benard convection planforms in a constant viscosity, high Prandtl number fluid. Internal heat generation is simulated by lowering the boundary temperatures at a constant rate. The Rayleigh number (RaT) based on the imposed temperature difference is l.5×105 and the Rayleigh number based on the amount of internal heat generation (RaH) is varied from 0 to 3.0×106. In the absence of internal heat generation the convection planforms are the symmetric spoke pattern in which connected spokes of ascending and descending flow have, on average, equal strength. With internal heat production, the planform is asymmetric with buoyancy concentrated in isolated descending arcuate trenches and circular plumes. The upwellings are nonbuoyant, although their planform is more connected than downwellings. The amount of time dependence is observed to increase with internal heat generation, and occurs by branching and propagation of the negatively buoyant trenches.