cssi/SciSciGPT-SciSciNet huggingface dataset:
On the Impact of Backoff Misbehaving Nodes in IEEE 802.11 Networks

In this paper, we address the problem of quantifying the impact of backoff misbehaving nodes in IEEE 802.11 networks. We propose two performance metrics, throughput gain ratio and throughput degradation ratio to quantify the performance gain of misbehaving nodes over legitimate nodes and the performance loss of legitimate nodes due to backoff misbehavior, respectively. We use asymptotic analysis to derive both throughput gain ratio and throughput degradation ratio in an IEEE 802.11 network in the presence of multiple misbehaving nodes. We show that, in general, the throughput gain ratio increases linearly with the number of legitimate nodes, and the throughput degradation ratio increases linearly with the number of misbehaving nodes. Finally, we use ns-2 simulations to validate our analytical results.
The anatomy and life‐history of a freshwater mollusk of the genus sphaerium

A detailed study has been made of the anatomy of one of the fingernail shells, and preliminary observations on the life-history have been carried out. In its general organization Sphaerium notatum is very similar to the larger fresh-water lamellibranchs. A gastric shield, crystalline style, and style sac, very similar to those found in the stomach and intestine of Lampsilis, are present. A pair of slender muscles extending from the dorsal side of the body into the gills, and evidently not previously described, have been found. The nervous system consists of the typical three pairs of lamellibranchiate ganglia, with their connectives, accessory ganglia, and nerve fibers. Particular study was given to the statocysts and osphradia, and attention is called to the fact that the function commonly ascribed to the osphradia is incompatible with their position in the roof of the cloacal chamber. S. notatum, like all the Sphaeriidae, is hermaphroditic and viviparous. The gonads are paired racemose glands lying behind and below the stomach. The sperm-producing follicles form the anterior portion of each gonad and are somewhat smaller and more numerous than the ova-producing follicles which form the posterior portion. The young pass through the early stages of development in brood pouches in the gills and are expelled as relatively enormous individuals. Preliminary observations on the life-history indicate that reproduction reaches its height in the summer and that fertilization probably takes place during the late summer and fall.
PRESENCE OF INTERLEUKIN 10 IN THE SERUM AND BLISTER FLUID OF PATIENTS WITH PEMPHIGUS VULGARIS AND PEMPHIGOID

Abstract Interleukin 10 (IL-10) is an immunoregulatory cytokine produced by T lymphocytes and macrophages. Recently, it has been suggested that IL-10 may be involved in the pathogenesis of various inflammatory and autoimmune diseases. Using an ELISA we investigated the presence of IL-10 in the serum and blister fluid of pemphigus vulgaris (PV) patients with active disease and those in prolonged clinical remission compared with normal controls. Sera from patients with bullous pemphigoid (BP), ocular cicatricial pemphigoid (OCP), oral pemphigoid (OP) and blister fluid from five patients with BP were also studied. Increased levels of IL-10 were detected in the sera of 87.5% of patients with active PV and were statistically significant ( P =0.0003) when compared with levels in normal human serum. Lower levels of IL-10 were detected in 12.5% PV patients in remission and were statistically significant ( P =0.0001) when compared with levels in patients with active disease. Levels of IL-10 were detected in sera of 4.6% (1 of 24) of the normal controls. The levels of IL-10 were approximately four times higher in blister fluids than levels in the serum in the same PV patients. This difference was highly statistically significant ( P =0.0008). A correlation was observed between serum levels of IL-10 and titres of pemphigus autoantibodies and with disease severity. Elevated level of IL-10 was detected in the blister fluid from five BP patients. Levels of IL-10 in the sera of patients with BP, OCP and OP were not significantly increased. These preliminary data suggest that IL-10 in concert with other cytokines may play an important role in the pathogenesis of PV and BP.
Short Wavelength Generation Using Excimer Lasers

High spectral brightness KrF* (249 nm) and ArF* (193 nm) excimer laser sources have been used in a variety of experiments to test the generation of coherent short wavelength radiation (λ ti 100 nm) using nonlinear processes. These experiments include harmonic generation, sum frequency mixing, two and four photon pumping of lasers as well as spectroscopic application of such short wavelength radiation and the study of nonlinear coupling at intensities of up to ≈ 10 17 W/cm 2 .
Adverse Events from Drug Therapy for Human Immunodeficiency Virus Disease

Purpose Drug therapies for patients with human immunodeficiency virus (HIV) infection are associated with adverse events that can potentially limit their effectiveness. We sought to quantify the incidence of these events in clinical practice and determine whether there were demographic and clinical differences in adverse event rates for these drugs. Patient and Methods We calculated specific and overall adverse event rates from use of zidovudine, didanosine, zalcitabine, cotrimoxazole, and dapsone in an observational urban cohort of 1,450 HIV-infected patients with a CD4+ count of 500 cells/mm 3 or less. We compared adverse event rates by gender, race, age, injecting drug use, and CD4+ count. Results Overall adverse event rates in order of incidence were dapsone, 16.2 per 100 person-years (PY); didanosine, 24.1 per 100 PY; zidovudine, 26.3 per 100 PY; cotrimoxazole, 26.3 per 100 PY; and zalcitabine, 37.0 per 100 PY. Rates increased significantly with decline in CD4+ count from >200 to + for all drugs but dapsone. In addition, women were more likely than men to have an adverse event for didanosine (relative risk [RR] = 2.7, P = 0.03 ) and from cotrimoxazole (RR 1.5; P = 0.05 ). Whites were at greater risk than blacks for adverse events from cotrimoxazole (RR = 1.6, P = 0.03 ). Only 22 of 357 total events (6%) required hospitalization, and there were no deaths. Conclusions Adverse events from antiretroviral drugs and Pneumocystis carinii pneumonia prophylaxis that interrupt therapy are relatively common, although serious events requiring hospitalization are rare. Adverse event rates increase progressively with decline in CD4+ count. The gender and race of the patient modify the risk of adverse events for some drugs.
Nancy J. Harm, Teacher, Humanitarian

Teacher and Humanitarian are the words selected by Dr. Nancy J. Harm's family to inscribe on her gravestone. Dr. Harm died January 4, 2009, after an 18-year battle with oral cancer. Dr. Harm had se...
Some interactions between dust from comet Shoemaker-Levy 9 and Jupiter

Dust components of Comet Shoemaker-Levy-9 will traverse Jupiter's magnetosphere for an extended period surrounding the July 1994 impact of the nuclear fragments with Jupiter's atmosphere. We focus here on three interactions that are, in principle, visible from Earth: one in which the magnetosphere could affect the comet, one in which the comet could affect the magnetosphere, and one caused by dust impacting the upper atmosphere. These interactions are (1) electrostatic disruption of dust grains, which could permit remote optical imaging of the magnetosphere, (2) energy degradation of trapped relativistic electrons, which might produce observable changes in their synchrotron emission spectrum, and (3) a coma-induced meteor shower in view of Earth-based telescopes. We find these various interactions may be weak, possibly unobservable. If these interactions prove detectable, they can provide unique diagnostic tools for the magnetosphere, the comet/magnetosphere interaction, and the mass flux and size distribution of dust striking the upper atmosphere.
Renal cortical necrosis and other lesions in sheep (with and without ligation of pancreatic duct) produced by Alloxan poisoning

Summary The effect of alloxan on normal sheep and on others in which the pancreatic duct had been ligated for variable periods was studied. If the animals survived there was, no appreciable difference in the reaction between the two groups as far as blood sugar findings were concerned, i.e. , the pancreatic sclerosis did not prevent, or was, not severe enough to prevent, the diabetogenic action of alloxan. The sheep was more susceptible tot a general toxic effect of alloxan. Although there was some individual variation of response, after a latent period they showed toxic effects manifested by a hyperacute illness due possibly to some violent, cardio-vascular upset, and the production of severe renal cortical necrosis which must have contributed to death.
A Snapshot of State Prison Libraries with a Focus on Technology

Abstract Current trends in prison libraries were explored, particularly in regards to technology. Adult state prisons were surveyed by mail nationwide. The 207 prisons in the sample were representative of the national population in terms of size, security level and sex distribution. Almost 97% had libraries offering a wide variety of print and electronic resources. Staffing, size and budgets varied widely. Almost half provided computers, but training was sporadic. Access to word processing, CDs and library catalogs were common. Only one librarian allowed access to the Internet with personal monitoring. All others found security risks too great.
Development of an algorithm for corneal reshaping with a scanning laser beam

The corneal-ablation rate, the beam-intensity distribution, and the initial and the desired corneal topographies are used to calculate a spatial distribution map of laser pulses. The optimal values of the parameters are determined with a computer model, for a system that produces 213-nm radiation with a Gaussian beam-intensity distribution and a peak radiant exposure of 400 mJ/cm2. The model shows that with a beam diameter of 0.5 mm, an overlap of 80%, and a 5-mm treatment zone, the roughness is less than 6% of the central ablation depth, the refractive error after correction is less than 0.1 D for corrections of myopia of 1, 3, and 6 D and less than 0.4 D for a correction of myopia of 10 D, and the number of pulses per diopter of correction is 2500 when the beam-intensity distribution is Gaussian and 580 when it is flat.
Empirical Evaluation of the Statement Deletion Mutation Operator

Mutation analysis is widely considered to be an exceptionally effective criterion for designing tests. It is also widely considered to be expensive in terms of the number of test requirements and in the amount of execution needed to create a good test suite. This paper posits that simply deleting statements, implemented with the statement deletion (SDL) mutation operators in Mothra, is enough to get very good tests. A version of the SDL operator for Java was designed and implemented inside the muJava mutation system. The SDL operator was applied to 40 separate Java classes, tests were designed to kill the non-equivalent SDL mutants, and then run against all mutants.
BitTorrent-inspired decentralized management of residential distributed energy resources (DER)

A novel decentralized approach to the management of residential distributed energy resources (DER) such as solar PV, wind, fuel cells, energy storage devices, and demand response (DR) is described. This new methodology treats residential electricity customers as peers in a BitTorrent-like power swarm, designed to efficiently dispatch local generation, storage, and demand response capacity to perform real-time demand-side load balancing without centralized control. It is envisioned that the technology could be implemented by utilities as an internet-based service layer that would allow more widespread integration of DER and smart devices within the existing power system. Initial MATLAB simulations of a 10-residence neighborhood with distributed generation (DG) demonstrate that BitTorrent is an effective protocol for decentralized load balancing, significantly reducing both local (peer) and aggregate (swarm) demand spikes.
Encoding specificity and integration of word pairs

Word concreteness was shown to have a differential effect on recognition-cued recall differences for noun-adjective pairs in a variant of the Tulving and Thomson (1973) paradigm. Consistent with the notion of integration of concrete word pairs, cued recall was superior to recognition for concrete-concrete pairs, but not for other pair types. For abstract-concrete and abstract-abstract pairs the data suggested that recognition was superior to recall. For concrete-abstract pairs there was no difference between recognition and recall.
A Comparison of Ultraviolet and Visible Raman Spectra of Supported Metal Oxide Catalysts

The recent emergence of ultraviolet-wavelength-excited Raman spectroscopy as a tool for catalyst characterization has motivated the question of how UV Raman spectra compare to visible-wavelength-excited Raman spectra on the same catalyst system. Measurements of Raman spectra from five supported metal oxide systems (Al2O3-supported Cr2O3, V2O5, and MoO3 as well as TiO2-supported MoO3 and Re2O7), using visible (514.5 nm) and ultraviolet (244 nm) wavelength excitation have been compared to determine the similarities and differences in Raman spectra produced at the two wavelengths. The samples were in the form of self-supporting disks. Spectra from the oxides, both hydrated as a result of contact with ambient air and dehydrated as a result of calcination or laser-induced heating, were recorded. A combination of sample spinning and translation to produce a spiral pattern of laser beam exposure to the catalyst disk was found to be most effective in minimizing dehydration caused by laser-induced heating. Strong ...
RStar: an RDF storage and query system for enterprise resource management

Modern corporations operate in an extremely complex environment and strongly depend on all kinds of information resources across the enterprise. Unfortunately, with the growth of an enterprise, its information resources are not only heterogeneous but also distributed in physically different systems and databases. How to effectively exploit information across the enterprise is becoming a critical but hard problem. In recent years, metadata which is the detailed description of the data is used to efficiently exploit information resources in the web. The World Wide Web Consortium (W3C) recommends the resource description framework (RDF) as a standard for the definition and use of metadata descriptions of resources in the web. In this paper, we present an RDF storage and query system called RStar for enterprise resource management. RStar uses a relational database as the persistent data store and defines RStar Query Language (RSQL) for resource retrieval. Currently, most of existing RDF storage and query systems are evaluated on small data sets and no detailed performance analysis is given for such systems. Therefore, we conduct extensive experiments on a large scale data set to investigate the performance problem in RDF storage. Such analysis will be helpful for designing RDF storage and query systems as well as for understanding not well-solved issues in RDF based enterprise resource management. In addition, experiences and lessons learned in our implementation are presented for further research and development.
Hepatic insulin extraction after major hepatectomy

Abstract Background: After major hepatectomy, the remaining liver compensates for its reduced mass and maintains euglycemia through increased hepatic glucose output. The mechanism of this compensation may be a diminished hepatic extraction of portal insulin, which thereby decreases the suppressive effects of insulin on gluconeogenesis. Methods: Extraction of insulin by the liver was measured using the isolated perfused rat liver model. Fasted Sprague-Dawley rats were studied at 1, 2, 3, 4, 6, and 14 days after 70% hepatectomy. Control rats had no operation, and sham rats were studied 1 day after a sham laparotomy. The difference between portal and caval insulin concentrations was determined and reported as micromoles of insulin extracted per gram liver per minute. Results: Insulin extraction decreased from 191 ± 22 μU/gm liver/min in control rats to 87 ± 13.2 μU/gm liver/min at postoperative day 1 ( p = 0.0001). Extraction normalized by postoperative day 6. Extraction rates in rats recovering from sham laparotomy were similar to control rats ( p = 0.088), suggesting that decreased extraction in hepatectomized rats was not due to postoperative stress. Conclusions: After 70% hepatectomy, the remaining liver extracts less insulin per gram. This may explain the ability of the reduced liver mass to maintain euglycemia after major hepatectomy. (Surgery 1998;123:415-20.)
Teachers' Verbal Corrections and Observers' Perceptions of Teaching and Learning:

We tested whether observers' perceptions of private lessons are affected by the type of verbalizations used by teachers to make corrections in student performance. We compared verbal corrections that were expressed as directive statements (i.e., specific directions to change some aspect of performance in a subsequent trial) and verbal corrections expressed as negative feedback statements (i.e., negative evaluations of student performance in a preceding performance trial). Participants viewed two videotaped private lessons. In one lesson, all corrections of student performance errors were expressed as directions to change some aspect of performance in the subsequent trial. In the other lesson, all corrections were expressed as negative feedback statements followed by a direction to play again. Subjects responded using a paper-and-pencil questionnaire with 10 statements about the teacher and student in each lesson. There were no meaningful differences in subjects' responses between the two lessons, both of ...
Predicting Health-related Quality of Life: Testing the Contextual Model Using Structural Equation Modeling

This study aims to investigate the utility of the Contextual Model of Health-Related Quality of Life (HRQOL) to explain the relationship among the domains of HRQOL with a diverse, population-based sample of breast cancer survivors (BCS). We employed a cross-sectional design to investigate HRQOL among 703 multiethnic, population-based BCS. The study methodology was guided by the Contextual Model of HRQOL. Structural Equation Modeling (SEM) was conducted to assess the hypothesized model. SEM identified significant relationships among the bio-psychological domain (general health status, cancer-related factors, and psychological factors), the cultural-socio-ecological domain (health care satisfaction, socio-ecological factor, and socio-economic status), and HRQOL. The best fitting model indicates direct pathways from ‘general health status’, ‘years since diagnosis’, ‘health care satisfaction’ and ‘socio-ecological factor’ to ‘HRQOL’ variables. Additionally, ‘socio-ecological factor’ and ‘socio-economic status’ variables were indirectly associated with HRQOL through ‘general health status’. Findings suggest that the Contextual Model of HRQOL adds valid factors to explain overall HRQOL and increases our understanding of the socio-ecological dimensions predicting HRQOL outcomes. The revelation of inter-relations among the dimensions of HRQOL may inform the translational and clinical utility of the HRQOL construct.
The NMR spectra of some 3-coordinate phosphorus compounds containing chloromethyl and isopropyl groups

Analysis of the proton NMR spectra of Pr1PCINMe2 indicates magnetic non-equivalence of the methyl groups due to the adjacent asymmetric phosphorus atom. High temperatures, or the addition of chloride ion, induce an exchange reaction with inversion of configuration at phosphorus. The corresponding fluoride is configurationally stable at high temperatures. The compounds CICH2PXNR2 (X = Cl, F; R = Me, Et) have non-equivalent protons in the chloromethyl group. The two HCP coupling constants in the chlorides of this series are of opposite sign, whereas in the fluorides they are of the same sign.
The Design Parameters for a Lithium Lens as Antiproton Collector

Maxwell's equations with appropriate boundary conditions are solved for a pulsed cylindrical conductor. The results are applied to the lithium lens used as an antiproton collector for the Fermilab p?p collider. The magnetic field is expressed as a function of radial distance and time. The time corresponding to maximum linearity is calculated. A method for measuring the current density at the surface is discussed and the Joule heat produced per pulse is calculated.
Modulation of NMDA-induced currents by μ-opioid receptor agonist DAGO in acutely isolated rat spinal dorsal horn neurons

Abstract The whole-cell patch-clamp technique was used to examine effects of μ-opioid receptor agonist Tyr- d -Ala-Gly-Me-Phe-Gly-ol-enkephalin (DAGO) on N- methyl- d -aspartate (NMDA)-induced currents in freshly enzymatically and/or mechanically dissociated rat spinal dorsal horn neurons (laminae I–III). Here we report that the responses of dorsal horn neurons to NMDA were modulated by DAGO in a complex manner. When applied simultaneously with, or prior to NMDA, DAGO (10–100 nM) initially suppressed the response to NMDA in 52% of examined cells. Following removal of DAGO, the NMDA responses were potentiated in 71% of the cells. The enhancing effect of DAGO was rapid in onset and lasted up to 50 min after removal of the peptide. Both the initial depressant and the late enhancing effect were reversed by naloxone. These results are consistent with the possibility that DAGO might directly modulate the NMDA receptor-ion channel complex and that this action may contribute to the regulation of the strength of excitatory amino acid-mediated primary afferent neurotransmission, including nociception.
Framing Further Considerations: Reply to Commentaries by Philip Bromberg and Glen Gabbard

This response to discussants Philip Bromberg and Glen Gabbard explores the relevance of a self-state perspective to my reflections (2007) on the benefits of reconsidering traditional recommendations regarding an analytic frame. The clinical and theoretical implications of Bromberg's view that the shifting choreography of a multiplicity of self-states of analyst and patient, in collision and negotiation, are implicated in the structuring and resructuring of an analytic frame, are considered. I also explore Gabbard's perspective that analysts' reliance on traditional, rigid constructions of an analytic frame no longer characterizes most contemporary work. Although I agree that relational contributions to psychoanalysis have become increasingly well established and that our more traditionally trained colleagues are beginning to grapple with and even integrate them to some degree, I nevertheless suggest that many of the traditional ways of defining and structuring a psychoanalytic frame continue to exercise a...
Coding online content-informed scaffolding of mathematical thinking

Abstract This article describes the Mathematical Mentoring Coding Scheme (MMCS), a coding scheme that identifies indicators relevant to the study of content-informed scaffolding. Content-informed scaffolding refers to the use of subject matter content in ill-defined problem spaces to focus the learner, and provide and fade feedback so that the learner becomes autonomous. It is suggested that the MMCS could also double as a rubric for instruction in content-informed scaffolding. Two case examples of preservice teachers’ scaffolding of elementary students’ problem solving serve as illustrations.
Scattering of Charged Particles in a Weakly Unstable Plasma

The mean‐square deflection of suprathermal test particles from a weakly unstable electron plasma is calculated. The instability is assumed to have been driven by a tenuous beam of energetic electrons. The random phase approximation expression for the spectral density is used and the electric field energy density of the turbulent spectrum is estimated by the quasilinear theory. It is shown that the mean‐square scattering angle can be increased by more than an order of magnitude by a suitable beam density or drift velocity. This enhances the potential usefulness of charged‐particle scattering as a diagnostic tool for turbulent laboratory plasmas.
Characterization of the subpellicular network, a filamentous membrane skeletal component in the parasite Toxoplasma gondii.

Abstract Electron microscopic examination of detergent-extracted Toxoplasma tachyzoites reveals the presence of a mechanically stable cytoskeletal structure associated with the pellicle of this parasite. This structure, composed of interwoven 8–10 nm filaments, is associated with the cytoplasmic face of the pellicle and surrounds the microtubule-based cytoskeleton. Two protein components of this network, TgIMC1 and TgIMC2, were identified. Both are novel proteins, but have a resemblance to mammalian filament proteins in that they are predicted to have extended, coiled-coil domains. TgIMC1 is also homologous to articulins, the major components of the membrane skeleton of algae and free-living protists. A homologue of TgIMC1 in the related malaria parasite Plasmodium falciparum was also identified suggesting the presence of structurally similar membrane skeletons in all apicomplexan parasites. We suggest that the subpellicular network, formed by TgIMC1 and 2 in Toxoplasma gondii and related parasites, plays a role in the determination of cell shape and is a source of mechanical strength.
Semi-blind channel estimation and detection using superimposed training

Channel estimation for single-input multiple-output (SIMO) time-invariant or slowly time-varying channels is considered using superimposed training. A periodic (non-random) training sequence is arithmetically added (superimposed) at a low power to the information sequence at the transmitter before modulation and transmission. Two versions of a two-step approach are adopted where in the first step, following [11], we estimate the channel using only the first-order statistics of the data. Using the estimated channel from the first step, a linear MMSE equalizer and hard decisions, or a Viterbi detector, are used to estimate the information sequence. In the second step a deterministic maximum likelihood (DML) approach or an approximation to it, is used to iteratively estimate the SIMO channel and the information sequences sequentially. Illustrative computer simulation examples are presented where we compare the proposed approaches to the conventional (time-multiplexed) training based approach.
Life Stories and the Psychosocial Construction of Careers

ABSTRACT This paper describes and interprets the narratives that middle-aged businessmen tell about their careers It draws a symbolic connection between these men's careers and the longings and frustrations of their childhood, revealed in part by the characters that populate these men's stories But the connection is also revealed by something more abstract the formal shape of their stories' plot These plots, which emphasize relentless forward movement, are shaped by career culture, which demands constant advancement But advancement is also a psychodynamic symbol It expresses men's aggressive self-aggrandizement, while denying their desire for affection and their vulnerability to rejection The result of this alliance between psychodynamic motives and social practices is that men pursue one type of recognition–that of aggressive achievement–while they systematically disavow their longing for more personal attachment
Hyperlipidemia associated with HIV protease inhibitor use: pathophysiology, prevalence, risk factors and treatment.

Despite potent antiretroviral activity, the HIV-1 protease inhibitors have recently been associated with abnormal serum lipoprotein concentrations. The purpose of this review is to describe serum lipid abnormalities related to protease inhibitor use. A MEDLINE search up to June 1, 1999, and abstracts from recent scientific meetings were primary data sources. Lipid disturbances in HIV-infected patients receiving protease inhibitors generally consist of elevated triglycerides and total cholesterol levels; HDL cholesterol is often reduced. The pathophysiological mechanism by which the protease inhibitors induce these lipid abnormalities has been hypothesized, but is unknown. Cases of pancreatitis and coronary heart disease have been described in hyperlipidemic patients receiving protease inhibitors. Treatment of protease inhibitor-related hyperlipidemia is unknown. Exchanging the offending protease inhibitor for nevirapine may be helpful in certain patients. Atorvastatin in combination with gemfibrozil has b...
Free Edges in Epithelial Cell Sheets Stimulate Epidermal Growth Factor Receptor Signaling

Epithelia tend to migrate when edges are present, for instance, after wounding or during development. Using a new tissue culture model, we found that the existence of free edges is in itself a sign...
Evolution of individuality during the transition from unicellular to multicellular life

Individuality is a complex trait, yet a series of stages each advantageous in itself can be shown to exist allowing evolution to get from unicellular individuals to multicellular individuals. We consider several of the key stages involved in this transition: the initial advantage of group formation, the origin of reproductive altruism within the group, and the further specialization of cell types as groups increase in size. How do groups become individuals? This is the central question we address. Our hypothesis is that fitness tradeoffs drive the transition of a cell group into a multicellular individual through the evolution of cells specialized at reproductive and vegetative functions of the group. We have modeled this hypothesis and have tested our models in two ways. We have studied the origin of the genetic basis for reproductive altruism (somatic cells specialized at vegetative functions) in the multicellular Volvox carteri by showing how an altruistic gene may have originated through cooption of a life-history tradeoff gene present in a unicellular ancestor. Second, we ask why reproductive altruism and individuality arise only in the larger members of the volvocine group (recognizing that high levels of kinship are present in all volvocine algae groups). Our answer is that the selective pressures leading to reproductive altruism stem from the increasing cost of reproduction with increasing group size. Concepts from population genetics and evolutionary biology appear to be sufficient to explain complexity, at least as it relates to the problem of the major transitions between the different kinds of evolutionary individuals.
Percutaneous Endovascular Repair of Aneurysm After Previous Coarctation Surgery

To the Editor: Using percutaneous catheter techniques and endovascular grafts, Ince et al1 reported successful treatment of aneurysms occurring after previous repair of aortic coarctation with no mortality and minimal morbidity in 6 patients. They contrasted these results with those reported for similar patients with open surgical treatment, in whom the mortality rates ranged between 14% and 23.5%. The 3 references reporting these outcomes …
To Click, Type, or Drag? Evaluating Speed of Survey Data Input Methods

The graphical user interface (GUI) used by Computer Assisted Telephone Interviewing (CATI) and web-based surveys offers researchers several options for inputting numeric data. Users can enter numeric values by typing a number, dragging an analog slider, or clicking a radio button. Because data entry is a ubiquitous task in modern society, researchers from many fields have explored ways to improve the efficiency of user interaction with input interfaces. We address a simple question: Is it faster to click, type, or drag? Results from two randomized experiments indicate that clicking is the fastest entry method followed by typing. In contrast, dragging is the slowest of the three interfaces.
Error exponents for the Gaussian multiple-access channel

We give random-coding error-exponent bounds for the Gaussian multiple-access channel (GMAC) Y_=AX_+N_, where X_ is the K/spl times/1 vector input, A is the M/spl times/K channel matrix, and N_ is a zero-mean Gaussian vector with full-rank covariance matrix N. The K users signal independently of each other, and the power of the k/sup th/ user is P/sub k/=E{X/sub k//sup 2/}. This vector-valued channel is a generalization of the scalar-valued conventional GMAC, Y=/spl Sigma//sub k=1//sup K/, X/sub k/+N, for which A=[1...1]; it arises in multiuser signaling schemes such as code-division and bandwidth-efficient multiple access (CDMA and BEMA). Error exponents give not only the capacity region of the channel, but also an indication of how the average probability of error decays as a function of the block length of random codes.
Bis-Enoxacin Blocks Rat Alveolar Bone Resorption from Experimental Periodontitis

Periodontal diseases are multifactorial, caused by polymicrobial subgingival pathogens, including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Chronic periodontal infection results in inflammation, destruction of connective tissues, periodontal ligament, and alveolar bone resorption, and ultimately tooth loss. Enoxacin and a bisphosphonate derivative of enoxacin (bis-enoxacin) inhibit osteoclast formation and bone resorption and also contain antibiotic properties. Our study proposes that enoxacin and/or bis-enoxacin may be useful in reducing alveolar bone resorption and possibly bacterial colonization. Rats were infected with 10(9) cells of polymicrobial inoculum consisting of P. gingivalis, T. denticola, and T. forsythia, as an oral lavage every other week for twelve weeks. Daily subcutaneous injections of enoxacin (5 mg/kg/day), bis-enoxacin (5, 25 mg/kg/day), alendronate (1, 10 mg/kg/day), or doxycycline (5 mg/day) were administered after 6 weeks of polymicrobial infection. Periodontal disease parameters, including bacterial colonization/infection, immune response, inflammation, alveolar bone resorption, and systemic spread, were assessed post-euthanasia. All three periodontal pathogens colonized the rat oral cavity during polymicrobial infection. Polymicrobial infection induced an increase in total alveolar bone resorption, intrabony defects, and gingival inflammation. Treatment with bis-enoxacin significantly decreased alveolar bone resorption more effectively than either alendronate or doxycycline. Histologic examination revealed that treatment with bis-enoxacin and enoxacin reduced gingival inflammation and decreased apical migration of junctional epithelium. These data support the hypothesis that bis-enoxacin and enoxacin may be useful for the treatment of periodontal disease.
Time to Sputum Culture Conversion in Multidrug-Resistant Tuberculosis: Predictors and Relationship to Treatment Outcome

Background: Conversion of sputum mycobacterial cultures from positive growth to negative growth of Mycobacterium tuberculosis in patients with pulmonary tuberculosis (TB) is considered the most important interim indicator of the efficacy of anti-TB pharmacologic treatment for multidrug-resistant disease. Objective: To evaluate and compare time to and predictors of initial sputum culture conversion with predictors of treatment outcome for patients with multidrug-resistant TB. Design: Retrospective cohort study. Setting: Latvia. Patients: All civilian patients with multidrug-resistant TB treated with the DOTS-Plus strategy between 1 January and 31 December 2000. Intervention: Individualized treatment for confirmed sputum culture–positive pulmonary multidrug-resistant TB. Measurements: Time to initial sputum culture conversion and treatment outcome. Results: Among 167 patients who were sputum culture–positive at initiation of second-line therapy, 129 (77%) converted in a median time of 60 days (range, 4 to 462 days) and 38 (23%) did not convert. Independent predictors of a longer sputum culture conversion time, using an accelerated failure time regression model, included previous treatment for multidrug-resistant TB, high initial sputum culture colony count, bilateral cavitations on chest radiography, and the number of drugs the initial isolate was resistant to at treatment initiation. Treatment outcomes were statistically significantly worse for patients who did not convert their sputum culture within 2 months. Limitations: Twenty-five percent of patients missed 5 or more monthly sputum collections. Conclusions: Under program conditions in Latvia, most patients with multidrug-resistant TB achieved sputum culture conversion within 12 weeks of starting treatment. Chest radiography and sputum culture drug susceptibility testing can assist physicians in predicting which patients will convert more slowly. Sputum culture conversion is a useful and appropriate interim indicator of treatment outcome in patients with multidrug-resistant TB.
Liver retransplantation for hepatitis C virus recurrence: a survey of liver transplant programs in the United States.

Background & Aims: Hepatitis C virus (HCV)-related liver failure is the leading indication for liver transplantation (LT). The number requiring re-LT is expected to grow as patients live long enough to develop graft failure and recurrent disease. Numerous factors have been identified as influencing survival after re-LT. To gain insight into how transplant centers are dealing with this issue and whether published prognostic factors are being used, we conducted a survey of liver transplant centers across the US in late 2003. Methods: Surveys consisting of 6 multiple-choice questions were sent to all 96 adult transplant medical directors in the US. Results: Fifty-five (57%) surveys were returned. Of these respondents, 95% would offer re-LT for allograft failure caused by recurrent HCV. A little more than half believed age >60 years and development of allograft cirrhosis after Conclusions: As of late 2003, nearly all surveyed transplant medical directors in the US would offer re-LT to recurrent HCV. Perceived practice patterns for re-LT are at variance with published outcome data.
Routing multimedia traffic with QoS guarantees

One of the challenging issues in exchanging multimedia information over a network is how to determine a feasible path that satisfies all the quality-of-service (QoS) requirements of multimedia applications while maintaining high utilization of network resources. The latter objective implies the need to impose an additional optimality requirement on the feasibility problem. This can be done through a primary cost function (e.g., administrative weight, hop-count) according to which the selected feasible path is optimal. In general, multiconstrained path selection, with or without optimization, is an NP-complete problem that cannot be exactly solved in polynomial time. Heuristics and approximation algorithms with polynomial- and pseudo-polynomial-time complexities are often used to deal with this problem. However, existing solutions suffer either from excessive computational complexities that cannot be used for online network operation or from low performance. Moreover, they only deal with special cases of the problem (e.g., two constraints without optimization, one constraint with optimization, etc.). For the feasibility problem under multiple constraints, some researchers have recently proposed a nonlinear cost function whose minimization provides a continuous spectrum of solutions ranging from a generalized linear approximation (GLA) to an asymptotically exact solution. In this paper, we propose an efficient heuristic algorithm for the most general form of the problem. We first formalize the theoretical properties of the above nonlinear cost function. We then introduce our heuristic algorithm (H/spl I.bar/MCOP), which attempts to minimize both the nonlinear cost function (for the feasibility part) and the primary cost function (for the optimality part). We prove that H/spl I.bar/MCOP guarantees at least the performance of GLA and often improves upon it. H/spl I.bar/MCOP has the same order of complexity as Dijkstra's algorithm. Using extensive simulations on random graphs and realistic network topologies with correlated and uncorrelated link weights from several distributions including uniform, normal, and exponential, we show the efficiency of H/spl I.bar/MCOP over its (less general) contenders in terms of finding feasible paths and minimizing their costs under the same level of computational complexity.
Simulating Microstructural Evolution using the Phase Field Method

The key to predict material properties is the state of microstructure. Because microstructural evolution is a typical nonlinear, nonlocal, and multiparticle dynamic problem, computer simulations play an ever increasingly important role in predicting key microstructural features and their time evolution during various processes such as phase transformations, domain coarsening, and plastic deformation. A plethora of computational methods and algorithms have been developed in recent years to complement theoretical and experimental studies to explore the high dimensional material- and processing-parameter space, which would not only lower the cost but also increase the efficiency of optimizing existing materials and developing new ones. In this article, a brief account of the basic features of each method, including the conventional front-tracking methods and techniques without front-tracking (such as Continuum/Microscopic/Coarse-Grained Phase Field Method; Mesoscopic/Atomistic Monte Carlo; Cellular Automata; Discrete Lattice Model; Phase Field Crystal Model; Diffusive Molecular Dynamics; Microscopic Master Equations; Inhomogeneous Path Probability Method; and Molecular Dynamics) will be presented first, followed by detailed descriptions of the fundamentals of various phase-field methods at different length scales and their model formulations. The applications of the phase field methods will be demonstrated by examples of coherent precipitation, grain growth, ferroelectric domain structure formation, dislocation core structures, and dislocation-precipitate interactions. Existing challenges and future trends of the phase-field methods are discussed at the end of the article. Keywords: precipitation; grain growth; dislocation; phase transformation; plastic deformation; Monte Carlo method; molecular dynamics simulation
Carotid baroreflex control of leg vascular conductance at rest and during exercise

We sought to test the hypothesis that the carotid baroreflex (CBR) alters mean leg blood flow (LBF) and leg vascular conductance (LVC) at rest and during exercise. In seven men and one woman, 25 ± ...
A robust acknowledgement scheme for unreliable flows

The increasing presence of UDP traffic in the Internet and the emergence of sensing applications which do not require full reliability motivates the search for a robust acknowledgement scheme for unreliable flows. TCP-styled cumulative ack relies on the eventual retransmission of all lost packets and hence cannot be used for unreliable flows. Our contribution is the design and analysis of a simple, yet robust acknowledgement scheme for unreliable flows. We show that our scheme achieves good performance even when the actual network conditions deviate from the designer's estimate. It works in networks having orders of magnitude difference in bandwidth and loss probability, with little variation of overhead and no change to the algorithms.
Channel-access and routing protocols to utilize multiple heterogeneous channels for ad hoc networks

We introduce new rules for channel access and a new metric for use with the routing protocol for ad hoc networks that utilize multiple heterogeneous channels. The networks we investigate employ frequency-agile radios that are able to change their carrier frequency and chip rate over a wide range of possibilities. These protocols have the capability to increase the network performance of an ad hoc network by utilizing the multiple bands available to the network. We show that our jointly designed channel-access and routing protocols significantly increase network performance over an approach in which the channelaccess and routing protocols are not designed to cooperate. We also show that the channel-access and routing protocols should be adapted jointly according to the specific characteristics of the network.
Teaching Online: Three Perspectives, Three Approaches

Online courses are growing in popularity, providing opportunities for individuals to complete their education while overcoming time and distance constraints. Innovations in distance education allow for the design and development of online courses that adapt to meet the specific needs and/or learning styles of the students enrolled, and reflect the unique teaching style and personality of the instructor. The purpose of this descriptive case study is to share three perspectives and three approaches of three faculty members who teach a range of graduate level educational technology courses at a university located in northeast Texas. Tips, techniques, lessons learned, and examples of proven interaction activities while meeting course objectives and addressing specific needs of students will be discussed.
Personality characteristics of college students on academic probation1

Summary In two separate studies underclassmen on academic probation (N = 27, N = 22) were individually matched for aptitude with academically satisfactory students to investigate (a) nonaptitudinal factors differentiating probation students from matched students and (b) how probation students who eventually have to withdraw differ from those who improve. Results based on interviews, questionnaires, and self-report measures indicate that probation students have unrealistically optimistic expectations concerning grades, attribute their difficulties to academic factors rather than personal concerns, and tend to be defensive, lacking in positive motivation for academic work, and relatively dependent on their parents. Students most likely to get off probation estimated their grades most accurately and had lowest test anxiety
Fatty Acid Composition of L-Forms of Streptococcus faecalis Cultured at Different Osmolalities

The fatty acid composition of the membranes of three different penicillin-produced L-forms of Streptococcus faecalis was determined: (i) a stable (nonreverting) L-form (T(53)) cultured in brain heart infusion (BHI) with 0.5 M sucrose; (ii) a stable L-form (T(531)) cultured in BHI without sucrose; and (iii) an unstable L-form (T(9)) cultured in BHI with 0.5 M sucrose and 1,000 U of penicillin per ml. L-forms were obtained by centrifugation and lysed by washing in 1 mM tris(hydroxymethyl)aminomethane-hydrochloride buffer. The parent S. faecalis was also cultured in BHI and BHI containing 0.5 M sucrose, and washed with buffer. The fatty acid composition of L-forms of S. faecalis cultured in BHI without sucrose (370 mosmol) had higher C(18:1) and lower C(18) than L-forms cultured in the same media with added 0.5 M sucrose (950 mosmol) in both exponential and stationary cultures. In the stationary phase of growth, C(19) was reduced in the L-forms cultured without sucrose. Similar changes were seen in the parent S. faecalis cultured in the two types of media. These changes in membrane fatty acids may relate to osmo-regulation of the L-forms.
E&HS aspects on metal recovery from electronic scrap

Inside the electronics we all use and enjoy a multitude of materials and substances does the work. Some of these materials are potentially hazardous to man or the environment. Smelters and refiners producing and handling some of these materials have long experience on how to treat and process toxic materials. The integration of new waste streams into the business of recycling has put forward new challenges. Drawing upon the internal control mechanisms and based on our long experience problems are detected, solutions implemented and the result monitored. In the paper the impact of recycling of electronic scrap on EH&S is discussed.