cssi/SciSciGPT-SciSciNet huggingface dataset:
Oil shales, evaporites and ore deposits

Abstract The relationships between oil shales, evaporites and sedimentary ore deposits can be classified in terms of stratigraphic and geochemical coherence. Oil shale and black shale deposition commonly follows continental red beds and is in turn followed by evaporite deposition. This transgressive-regressive sequence represents an orderly succession of depositional environments in space and time and results in stratigraphic coherence. The amount of organic carbon of a sediment depends on productivity and preservation, both of which are enhanced by saline environments. Work on Great Salt Lake. Utah, allows us to estimate that only 5% of TOC originally deposited is preserved. Inorganic carbonate production is similar to TOC production, but preservation is much higher. Oil shales and black shales commonly are enriched in heavy metals through scavenging by biogenic particles and complexation by organic matter. Ore deposits are formed from such rocks through secondary enrichment processes, establishing a geochemical coherence between oil shales and ore deposits. The Permian Kupferschiefer of N. Europe is used as an example to define a Kupferschiefer type (KST) deposit. Here oxygenated brines in contact with red beds become acidified through mineral precipitation and acquire metals by dissolving oxide coatings. Oxidation of the black shale leads to further acid production and metal acquisition and eventually to sulfide deposition along a reducing front. In order to form ore bodies, the stratigraphic coherence of the red bed-black shale-evaporite succession must be joined by the geochemical coherence of the ore body-evaporite-black shale association. The Cretaceous Cu-Zn deposits of Angola, the Zambian Copperbelt as well as the Creta, Oklahoma, deposits are other KST examples. In the Zambian Copperbelt, evaporites are indicated by the carbonate lenticles thought to be pseudomorphs after gypsum-anhydrite nodules. MVT deposits are also deposited by acid brines, but at more elevated temperatures and with carbonates as principal host rocks. The Pine Point deposits are cited for their close association with evaporites. Alkaline, metal-rich brines are postulated for the HYC deposit of McArthur River, Australia. Such brines are known from the Green River Formation and deposits formed from such brines constitute the GRT class. They can be recognized by the presence of Magadi-type cherts and zeolite-analcime-K-spar tuffs. The Cu-Co ore bodies of Outokumpu, Finland, might also belong to this type. A new classification of sedimentary ore deposits is proposed, based on their geochemical environment. KST and MVT are formed from acid ore fluids, while GRT and CT (Creede type) are derived from basic ore fluids. pH of the fluids is best evaluated not from the ores themselves, but from their effect on the host-rocks.
Fate of reversing factor during restoration of protein synthesis by hemin or GTP in heme-deficient reticulocyte lysates.

The inhibition of protein synthesis in hemedeficient reticulocyte lysates is reversed by the addition of hemin (20 microM) or MgGTP (2 mM). The rate of recovery is rapid and approaches control kinetics within a few minutes after the addition of either component. The restoration of protein synthesis is dependent upon the availability of functional reversing factor (RF). The fate of RF was monitored during recovery by using a method that measures RF activity in the lysate under physiological conditions. In the fully inhibited lysate, RF is sequestered in a nondissociable 15S [RF . eIF-2(alpha P)] complex (where eIF-2 indicates eukaryotic initiation factor 2) in which RF activity is not functional and cannot be assayed. The first step in the rescue of protein synthesis in inhibited lysates by hemin or MgGTP is the inhibition of heme-regulated eIF-2 alpha kinase, which enables endogenous phosphatase to dephosphorylate eIF-2(alpha P) and [RF . eIF-2(alpha P)]. The release of approximately 50% of the sequestered RF activity is sufficient to support optimal kinetics of recovery. Hemin and MgGTP both reverse inhibition by blocking the activation and/or activity of heme-regulated eIF-2 alpha kinase in the lysate. The conclusion that MgGTP exerts its effect on eIF-2 alpha kinase is supported by several in vitro findings: (i) 2 mM MgGTP inhibits the autophosphorylation of purified heme-regulated eIF-2 alpha kinase and abolishes its ability to phosphorylate eIF-2 alpha; (ii) 2 mM MgGTP cannot displace GDP in the binary complexes [eIF-2 . GDP] or [eIF-2(alpha P) . GDP] by mass action; and (iii) RF in the [RF . eIF-2(alpha P)] complex is not dissociated by 2 mM MgGTP.
Evaluation of the Finger and Phalange Froce Distributions in Pulling Task

The pulling finger/phalange force distributions were investigated with various handles. Generally, oval handles required higher forces than double frustum handles in pulling task. The finger force distributions of the pulling task were similar to those of the gripping task. Middle (28%) and index (27.2%) were the strongest and little (20.8%) showed the lowest, followed by ring (23.9%). However, the phalange force distributions of the pulling task were different from the gripping task. Proximal (37.6%) produced the largest and middle (33.6%) also exerted more forces than distal (28.8%) phalanges. As the handle size increased, the forces of index and middle fingers showed increasing trends while ring and little fingers had decreasing trends. The phalange force was being moved more on distal phalanges than on proximal and middle phalanges. The understanding of force distributions may help to develop biomechanical finger models and to design hand tools for reducing related hand injuries.
Atrial fibrillation degenerates into ventricular fibrillation.

![Figure][1] A 43-year-old man with paroxysmal atrial fibrillation (AF) and an implantable cardioverter defibrillator (ICD) placed for documented ventricular fibrillation (VF), presented with an ICD shock. Ventricular pre-excitation was not present. Interrogation of his ICD demonstrated AF
Time reversal and Lanczos iterations

We describe a new time-reversal algorithm capable of focusing on multiple scatterers in a relatively small number of iterations. We recognize that the traditional time-reversal method is based on utilizing power iterations to determine the dominant eigenpairs of the time-reversal operator. The convergence properties of these iterations are known to be sub-optimal. Motivated by this we propose and describe a new time-reversal method based on Lanczos iterations. We consider a simplified scatterer identification problem and compare the performance of the Lanczos and power iterations based methods. We conclude that for the same number of transmitted and received signals, the Lanczos iterations based approach is substantially more accurate.
Sex stereotyping in children's toy advertisements

Forty-eight categories of toys were rated in terms of sex appropriateness by 48 students. A sample of 392 pictures of children with toys in 12 toy catalogs and 538 pictures of children with toys on toy packages in four retail stores was coded according to toy type and sex(es) of children shown. The rated sex stereotype of the toy category proved to be very strongly related to the sex(es) of the children shown with the toy in catalogs (r=.89) and on toy packages (r=.87). Toys rated as moderately sex typed by raters were just as strongly stereotyped in toy advertisements as those rated as strongly sex typed.
Photoisomerization of cis-1,2-di(1-Methyl-2-naphthyl)ethene at 77 K in Glassy Media.

cis-1,2-Di(1-methyl-2-naphthyl)ethene, c-1,1, undergoes photoisomerization in methylcyclohexane, isopentane and diethyl ether/isopentane/ethanol glasses at 77 K. On 313 nm excitation the fluorescence of c-1,1 is replaced by fluorescence from t-1,1. Singular value decomposition reveals that the spectral matrices behave as two component systems suggesting conversion of a stable c-1,1 conformer to a stable t-1,1 conformer. However, the fluorescence spectra are kexc dependent. Analysis of global spectral matrices shows that c-1,1 is a mixture of two conformers, each of which gives one of four known t-1,1 conformers. The kexc dependence of the c-1,1 fluorescence spectrum is barely discernible. Structure assignments to the resolved fluorescence spectra are based on the principle of least motion and on calculated geometries, energy differences and spectra of the conformers. The relative shift of the c-1,1 conformer spectra is consistent with the shift of the calculated absorption spectra. The calculated structure of the most stable conformer of c-1,1 agrees well with the X-ray crystal structure. Due to large deviations of the naphthyl groups from the ethenic plane in the conformers of both cand t-1,1 isomers, minimal motion of these bulky substituents accomplishes cis ? trans interconversion by rotation about the central bond.
Why Does Kevlar Decompose, while Nomex Does Not, When Treated with Aqueous Chlorine Solutions?

Kevlar and Nomex are high-performance polymers which have wide varieties of applications in daily life. Recently, they have been proposed to be biocidal materials when reacted with household bleach (sodium hypochlorite solution) because they contain amide moieties which can be chlorinated to generate biocidal N-halamine functional groups. Although Nomex can be chlorinated without any significant decomposition, Kevlar decomposes under the same chlorination conditions. In this study, two mimics for each of the polymers were synthesized to simulate the carboxylate and diaminophenylene components of the materials. It was found that the p-diaminophenylene component of the Kevlar mimic is oxidized to a quinone-type structure upon treatment with hypochlorous acid, which then decomposes. However, such a mechanism for the Nomex mimic is not possible. In this paper, based upon these observations, a plausible answer will be provided to the title question.
Generalized Q-space imaging reveals complex muscle architecture in vivo

Muscle tissue architecture is difficult to probe in terms of biophysical interactions due to large-scale hierarchical composition, ranging from the molecular to the organ scale. To address this need, we developed a generalized Q-space imaging approach employing fundamental concepts of diffusion-weighted magnetic resonance imaging (DW-MRI). This approach considers the morphology and distribution of magnetic field gradients, and results in the generation of a probability distribution function (PDF) for diffusivity at the voxel scale to describe multi-cellular diffusional boundaries within muscle. The principal fiber populations identified within these PDFs were associated by streamlines to create multi-voxel tracts that depict the orientation of muscle fibers at the tissue scale. Computational simulations of Q-space paradigms, where the B-value was defined as a model input describing diffusion distance and time and where Q-space was considered to have either spherical or hemispherical morphology, were performed. These simulations resulted in a quantitative description of crossing and tracking angles, thereby delineating the geometric precision of the method. We applied this imaging approach in an MRI experiment of the human tongue in vivo, using a shell distribution (single B-value) or segmented distribution (spectrum of B-values) with directionality defined by Q-space morphology, and confirmed the capacity to image complex muscular interfaces in vivo. We propose that this method may be applicable for defining normal and abnormal muscular architectural phenotypes.
Visual demonstrations of performance characteristics of surface surveillance

In this paper we describe the use of visual demonstrations (both still images and videos) to aid air traffic control subject matter experts (SMEs) in estimating the required performance characteristics for a surface surveillance system. The demonstrations focused on performance characteristics of location accuracy, orientation accuracy, latency, and update rate. The demonstrations were aimed to increase validity of performance characteristic estimates by allowing SMEs to visualize the consequences in an airport surface context. Still images were created to show the impact of surveillance error for aircraft location and orientation by depicting an opaque aircraft location on a satellite image and using ghost images to depict error. Videos of aircraft moving on and around the airport surface were created to show how surveillance with a specified latency or reduced update rate would appear. These demonstrations influenced the value and variability of performance characteristic estimates, relative to initial discussions without visual demonstrations. The visual demonstrations also increased the consensus and confidence that the team had in the estimates. The distinct advantage of the visual demonstrations is that they elicited performance characteristics estimates that were more valid than simple verbal discussions of values, while being less expensive and faster than full human-in-the-loop simulations.
Improved parallel algorithms for the depth-first search and monotone circuit value problems

Parallel algorithms for ordered depth-first search (ODFS) and the monotone circuit value (MCV) on parallel random access machines (PRAMs) and single bus multiprocessors are presented. While it is known that these problems are log-space complete for P and hence unlikely to have poly-logarithmic time parallel solutions, parallel algorithms that achieve a speedup linear in the number of processors (albeit within a limited range) are of considerable practical interest. In this paper we present parallel algorithms for these problems that require O(m/p + n) time on a p processor Concurrent Read Exclusive Write (CREW) PRAM, where n is the number of vertices and m the number of edges in the problem graph. This bound has previously been achieved only on more powerful PRAM models, namely the arbitrary Concurrent Read Concurrent Write (CRCW) PRAM for the MCV problem and the priority CRCW PRAM for the ODFS problem. Our technique permits us to implement these algorithms efficiently on single bus multiprocessor architectures in time O(n2/p) for 1 ≤ p ≤ n. An interesting consequence of our algorithms is that the problems of finding the connected components, the biconnected and bridge connected components of an undirected graph, and the strongly connected components of a directed graph can all be solved with the same processor and time complexities.
Personal therapy for family therapy graduate students

This study explores students' attitudes about personal therapy as a component of training and assesses the effects of providing a list of community therapist who were willing to see family therapy graduate students at a reduced fee on students' behaviors. Students' personal therapy experiences and attitudes about faculty involvement in their personal lives were also investigated. Most students believe that student therapists should have personal therapy sometime during their training, and the majority of students had al-ready been in therapy. Individual issues and relationship problems were the most frequently cited reasons for starting personal therapy.
Automatic construction and evaluation of performance skeletons

The performance skeleton of an application is a short running program whose execution time in any scenario reflects the estimated execution time of the application it represents. Such a skeleton can be employed to quickly estimate the performance of a large application under existing network and node sharing. This paper presents a framework for automatic construction of performance skeletons of a specified execution time and evaluates their use in performance prediction with CPU and network sharing. The approach is based on capturing the execution behavior of an application and automatically generating a synthetic skeleton program that reflects that execution behavior. The paper demonstrates that performance skeletons running for a few seconds can predict the application execution time fairly accurately. Relationship of skeleton execution time, application characteristics, and nature of resource sharing, to accuracy of skeleton based performance prediction, is analyzed in detail. The goal of this research is accurate performance estimation in heterogeneous and shared computation environments.
Simian Immunodeficiency Virus Infection Induces Expansion of α4β7+ and Cytotoxic CD56+ NK Cells

Herein we demonstrate that chronic simian immunodeficiency virus (SIV) infection induces significant upregulation of the gut-homing marker α4β7 on macaque NK cells, coupled with downregulation of the lymph node-trafficking marker, CCR7. Interestingly, in naive animals, α4β7 expression was associated with increased NK cell activation and, on CD16+ NK cells, delineated a unique dual-function cytotoxic-CD107a+/gamma interferon (IFN-γ)-secreting population. However, while SIV infection increased CD107a expression on stimulated CD56+ NK cells, α4β7+ and α4β7− NK cells were affected similarly. These findings suggest that SIV infection redirects NK cells away from the lymph nodes to the gut mucosae but alters NK cell function independent of trafficking repertoires.
Assessing the impact of image compression on SAR automatic target detection and cuing

We present the results of a recent study on the impact of data compression on automatic target cuing (ATC) in magnitude-detected SAR imagery. Four "off-the-shelf" compression algorithms were tested: JPEG, an optimally-pruned tree-stuctured vector quantizer (PTSVQ), a wavelet coder with scalar quantization, and a hybrid wavelet/PTSVQ coder. At compression ratios of 2:1 and 1:1, all four compression algorithms yielded a similar image quality and we observed no statistically significant impacts on ATC performance. We also evaluated the impact of a noisy transmission channel on the overall system performance and found no measurable ATC performance loss at bit error rates of 10/sup -5/ when error mitigation techniques were used.
Internet toasters as a capstone design project

One of the first devices connected to the Internet for remote control in 1990 was a (literal) toaster. Since then, the term "Internet toaster" has come to denote any small device connected to the Internet, particularly for the purposes of remote control or monitoring. Such devices are a topic of much current research and development. The vision of the Internet as a home control network has captured people's imaginations. The design of such devices makes for an ideal capstone design project. Such projects can emphasize hardware and/or software, can involve detailed study of network protocols or not, can be done with 8-bit microcontrollers or 80x86 embedded PCs, and can be as small or large as the environment requires. In addition, they can easily be multidisciplinary. This paper presents guidelines for instructors on how to choose and implement such a design project, along with an example of one such project - the Internet thermostat, which was a capstone design project at Bob Jones University in 1999.
Melnikov-based dynamical analysis of microcantilevers in scanning probe microscopy

We study the dynamical behavior of a microcantilever-sample system that forms the basis for the operation of atomic force microscopes (AFM). We model the microcantilever by a single mode approximation. The interaction between the sample and the cantilever is modeled by a Lennard--Jones potential which consists of a short-range repulsive potential and a long-range van der Waals (vdW) attractive potential. We analyze the dynamics of the cantilever sample system when the cantilever is subjected to a sinusoidal forcing. Using the Melnikov method, the region in the space of physical parameters where chaotic motion is present is determined. In addition, using a proportional and derivative controller, we compute the Melnikov function in terms of the parameters of the controller. Using this relation, controllers can be designed to selectively change the regime of dynamical interaction.
Synthesis of new quinolinequinone derivatives and preliminary exploration of their cytotoxic properties.

A series of 7-amino- and 7-acetamidoquinoline-5,8-diones with aryl substituents at the 2-position were synthesized, characterized, and evaluated as potential NAD(P)H:quinone oxidoreductase (NQO1) -directed antitumor agents. The synthesis of lavendamycin analogues is illustrated. Metabolism studies demonstrated that 7-amino analogues were generally better substrates for NQO1 than 7-amido analogues, as were compounds with smaller heteroaromatic substituents at the C-2 position. Surprisingly, only two compounds, 7-acetamido-2-(8′-quinolinyl)quinoline-5,8-dione (11) and 7-amino-2-(2-pyridinyl)quinoline-5,8-dione (23), showed selective cytotoxicity toward the NQO1-expressing MDA468-NQ16 breast cancer cells versus the NQO1-null MDA468-WT cells. For all other compounds, NQO1 protected against quinoline-5,8-dione cytotoxicity. Compound 22 showed potent activity against human breast cancer cells expressing or not expressing NQO1, with respective IC50 values of 190 nM and 140 nM and a low NQO1-mediated reduction ra...
Development and application of an instrument for the measurement of directional emittance of blackbody cavities.

Reflectance measurements of directional spectral emittance of black body cavities with specific geometries, using laser source and integrating hemi-ellipsoid
Simulating management effects on crop production, tile drainage, and water quality using RZWQM–DSSAT

The objective of this study was to explore if more crop-specific plant growth modules can improve simulations of crop yields, and N in tile flow under different management practices compared with a generic plant growth module. We calibrated and evaluated the Root Zone Water Quality Model (RZWQM) with the Decision Support for Agrotechnology Transfer (DSSAT v3.5) plant growth modules (RZWQM–DSSAT) for simulating tillage (NT — no till, RT — ridge till, CP — chisel plow, and MP — moldboard plow), crop rotation {CC — continuous corn, and CS — corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]}, and nitrogen (N) (SA — single application at preplant, and LSNT — late spring soil N test based application) and manure (SM — fall injected swine manure) management effects on crop production and water quality. Data from 1978 to 2003 from a water quality experiment near Nashua (Nashua experiments), Iowa, USA, were used. The model was calibrated using data from one treatment plot and validated for the rest of the plots. Simulated management effects on annual N loading in tile flow were agreeable with measured effects in 85%, 99%, 88%, and 78% of the cases for tillage, crop rotation (CS vs. CC), N application timing (SA vs. LSNT), and swine manure applications (SM vs. SA), respectively. On average, the LSNT plots were simulated to have 359 kg ha �1 higher corn yield compared to SA, when the observed increase was 812 kg ha �1 . Grain yield simulations were not sensitive to differences between RT and NT, between SM and SA treatments, and between CS and CC. We conclude that considering the uncertainties of basic input data, processes in the field, and lack of site specific weather data, the results obtained with this RZWQM–DSSAT hybrid model were not much better than the results obtained earlier with the generic crop growth module. © 2007 Elsevier B.V. All rights reserved.
Is Littoral Habitat Affected by Residential Development and Land Use in Watersheds of Wisconsin Lakes

We measured differences in nearshore littoral zone habitat among lakes with different amounts of residential development and different patterns of watershed land use. Sampling stations were located at randomly selected sites within the nearshore littoral zone of limnologically similar lakes. An index of development density (based on counts of residential structures) and watershed cover types detected by satellite imagery summarized human influence in the riparian zone and watershed. To compare effects of development at local sites to effects of cumulative development density (structures/km shoreline), we used analysis of covariance. Quantity of woody debris, emergent vegetation and floating vegetation decreased at developed sites and in lakes with greater cumulative lakeshore development density. Littoral sediments contained more fine particles at developed sites and in lakes with greater development density. Sediment composition, quantity of vegetation, and woody debris were weakly associated with differences in watershed land use. Cumulative changes to watersheds and riparian zones are associated with measurable differences in littoral habitat that may not be detectable at smaller scales. For effective conservation, regulatory programs should consider the cumulative effects of development and land use on aquatic systems.
Inquiring into Teaching: Lesson Study in Elementary Science Methods

This article describes an innovative approach to developing preservice elementary science teachers’ classroom confidence and skills. Based on lesson study approaches, preservice candidates designed and taught integrated science–mathematics lessons during the semester before their student teaching. Working in teams, candidates designed and taught a common lesson in 3 different classrooms, critiquing and refining their lesson between each teaching activity. Data collected from observations of classroom teaching events, team reports, and individual reflections were analyzed qualitatively. Results indicate that, over the 3 teaching events, there were dramatic improvements in lesson design and delivery, the management of the learning environment, the quality of students’ engagements with meaningful content, and the quality of assessments and generation of student data.
A micromachining-based technology for enhancing germanium light emission via tensile strain

Scientists employ a micromachining-based technology to achieve significant enhancements in light emission from highly strained germanium-on-insulator samples.
Importance of coronavirus negative-strand genomic RNA synthesis prior to subgenomic RNA transcription

The (-)-strand viral RNAs that result from after infection of cells with coronaviruses, which possess RNA genomes of message polarity, are genomic-sized and subgenomic-sized. Each of the (-)-strand subgenomic RNAs corresponds in size to each of the subgenomic mRNA species that are made in infected cells. We tested whether (-)-strand subgenomic RNAs might initially be synthesized from the input single-stranded (+)-strand genomic RNA prior to the production of subgenomic mRNAs. We used a mouse hepatitis virus (MHV) defective interfering (DI) RNA. from which subgenomic RNA was produced in DI RNA-replicating cells, because this DI RNA had a functional MHV intergenic region inserted in its interior. MHV samples containing the DI particles were irradiated with UV-light and then superinfected into cells that had been infected with MHV 4 h prior to superinfection. Northern blot analysis of intracellular RNAs that were extracted 3 h after superinfection showed that genomic DI RNA and subgenomic DI RNA had similar UV-target sizes, indicating that (-)-strand genomic DI RNA synthesis from input genomic DI RNA probably occurred prior to the subgenomic-size DI RNA synthesis. We discuss why, in the course of coronavirus transcription, (-)-strand genomic-length coronavirus RNA synthesis might occur before subgenomic-sized RNAs of either polarity are made.
Personal Influence and the Effects of the National Youth Anti-Drug Media Campaign

Personal Influence (Katz and Lazarsfeld 1955/2006) put forward and tested a variety of hypotheses about how social contexts constrain media effects. Five such hypotheses are described: three about interactions of media exposure with social context (Stability, Conformity, and Instrumental) and two about two-step flow effects (Relay and Message Interpretation). Each is tested here with data from the evaluation of the National Youth Anti-Drug Media Campaign. The evaluation of the campaign has suggested boomerang outcomes—more exposure to the campaign led to more interest in marijuana use. This article examined whether those effects were magnified through interactions with siblings. In general, no evidence showed that older siblings' beliefs or behavior interacted with younger siblings' exposure to campaign messages in producing effects. However, evidence showed that the two-step flow did operate: older siblings were themselves affected by their own exposure to the campaign and, in turn, affected the beliefs ...
Natural history and clinical outcome of sporadic renal cortical tumors diagnosed in the young adult.

Abstract Objectives To determine the natural history of patients younger than 40 years (young patient [YP] group) who are diagnosed with a sporadic renal cortical tumor (RCT) and to compare the natural history of these patients with the more typical older patient (OP) with RCT. Methods We reviewed our database and identified 34 patients (younger than 40 years old, median age 35) who underwent surgery for a sporadic RCT. The YP group outcomes were compared with 100 patients between 41 and 85 years (median 65). We fit a Cox proportional hazards model to examine the relationship between age at presentation and recurrence risk. Results The median tumor size in the YP group was 3.8 cm (range 0.6 to 19) and in the OP group was 5.0 cm (range 0.9 to 22; P = 0.225). Tumors were discovered incidentally in 51% and 56% of the YP and OP groups, respectively ( P = 0.65). The frequency of partial nephrectomy did not differ between the two groups (35% YP and 30% OP, P = 0.55). The frequency of malignant histologic subtypes did not differ between the groups ( P = 0.439). In the YP group, only larger tumor size (hazard ratio 1.23, 95% confidence interval 1.02 to 1.50, P = 0.034) was associated with a statistically significant increased risk of recurrence. Those in the YP group were not more or less likely to develop recurrence than those in the OP group (hazard ratio 0.79, 95% confidence interval 0.22 to 2.85, P = 0.72). The 5-year disease-free survival rate was 73% and 80% in the YP and OP groups, respectively ( P = 0.23). The 5-year disease-specific survival rate was 85% and 84% in the YP and OP groups, respectively ( P = 0.88). Conclusions The findings of our study indicate that the natural history of RCTs is similar in both younger and older patients. Young patients were neither more nor less likely to develop recurrence compared with their older counterparts.
Real-time sensing of tooth position for dental digital subtraction radiography

Dental digital subtraction radiography and accurate repositioning of the patient and X-ray source in order to facilitate correct diagnostics of bone loss are considered. Present mechanical repositioning systems do not allow radiography of posterior teeth and are uncomfortable for the patient. A repositioning system having a six degree-of-freedom position sensor and a robot arm with an X-ray source is proposed. A mathematical model for the system is given, and the robot arm solution is obtained based on patient position. An error analysis is performed in order to determine the influence of sensor and robot errors on system accuracy. A series of experiments to determine sensor noise and accuracy are described. These tests showed relatively small errors over the work envelope of the sensor. Further tests showed that there is no adverse effect due to the presence of metal work in the patient's mouth. The high bandwidth of the sensor may allow real-time tracking of small movements of the patient's head. >
Metastatic renal cancer: better never than late.

Approximately 30% of patients undergoing resection of clinically localized renal carcinoma with curative intent will develop metastatic disease recurrence [1]. Like all solid tumors, renal carcinoma is a clinically heterogeneous disease, and these recurrences occur with variable kinetics. Although most recurrences occur within 3 yr of surgery, approximately 10% of recurrences occur beyond 5 yr [2]. Prior research efforts have focused on better understanding the characteristics of primary tumors associated with these late recurrences [3] in an attempt to optimize postoperative surveillance strategies. However, until now, the outcomes in patients with late recurrences have been relatively unexplored. In this month’s issue of European Urology, Kroeger et al. describe the response to ‘‘targeted’’ treatment and survival in patients with late relapse from renal carcinoma (defined as >5 yr from surgery with curative intent) using a large retrospective database [4]. Interestingly, the authors report that 26% of 1210 patients with metastatic renal carcinoma experienced late relapse. The median time to late relapse was 8.5 yr. Late relapse was associated with better baseline prognostic features (eg, lower grade, fewer sarcomatoid features), a better objective response rate to targeted therapy, and longer progression-free and overall survival. When controlling for known prognostic variables, however, the survival improvement associated with late relapse was no longer statistically significant. These findings are immediately translatable to the clinic, providing reassurance to clinicians that patients with late relapses may be managed using conventional systemic therapy guidelines. Unfortunately, despite relatively better prognostic features and outcomes compared with patients with earlier relapses, patients with late relapses still succumbed to metastatic renal carcinoma. Our understanding of the biology surrounding the kinetics of tumor recurrence is at a stage of relative infancy. What can we learn from the study by Kroeger et al. [4] that may provide additional insights into this biology? The finding that lower grade tumors with better prognostic features were more commonly associated with late relapse raises the possibility that the micrometastases in these patients grew continuously from the time of initial dissemination, albeit at a relatively indolent rate, until the time they became clinically apparent, consistent with the proposed ‘‘continuous growth’’ model [5]. However, other models,
Competing Discourses on the Political Economy of Hunger

Among poor nations whose people suffer from hunger and malnutrition, talk about hunger and malnutrition appears to dictate the action (or lack of action) that will be taken to alleviate the suffering. In Puerto Cabezas, Nicaragua, where hunger and malnutrition are common, subtle differences concerning the interpretation of the causes of hunger exist among mothers of hungry children and professionals who provide services to them. Such differences are influential in the perpetuation of hunger and malnutrition. These competing discourses underplay (in many cases, even ignore) the political economy of hunger. This paper argues these disjunctures in the discourses of hunger take the spotlight off what is the ultimate root of hunger — namely, the neoliberal policies of the Nicaraguan government.
Concomitant Peripheral Arterial Disease and Coronary Artery Disease Therapeutic Opportunities

In the decade ahead, patients and primary care physicians will increasingly recognize the clinical burden of peripheral arterial disease (PAD). As new advances in the treatment of coronary artery disease continue to reduce mortality and morbidity, caregivers will increasingly confront the problem of concomitant “noncoronary” arterial disease. Cardiovascular physicians should assume a more proactive clinical role, along with their vascular medicine colleagues, to encourage new therapeutic opportunities for the treatment of arterial disease affecting multiple vascular beds. Multivascular therapeutic approaches are needed because atherosclerosis has a common systemic pathogenesis and simultaneously affects multiple circulations. Deployment of PAD therapies must be guided by an appreciation of the diverse natural histories associated with peripheral arterial diseases. Ideal patient-focused clinical outcomes may be defined when: (1) coronary therapies improve myocardial perfusion, reduce the risk of myocardial infarction and heart failure, and improve patient survival; (2) carotid therapies permit survival with reduced incidence of stroke; (3) renal artery disease therapies diminish the need for renal replacement therapies (dialysis and transplantation); and (4) lower-extremity PAD therapies improve functional status, foster wound healing, and decrease amputation rates. The achievement of health without amputation, stroke, end-stage renal failure, or myocardial infarction will require clinical wisdom. The calculation of risk/benefit ratios becomes increasingly complex with multi-circulation intervention and should be calibrated to the individual at risk. Patients with diffuse atherosclerotic disease traditionally have sought consultation and care from multiple specialists. The subspecialty of vascular medicine provides coordinated diagnostic and therapeutic efforts using a team approach. The case examples discussed below illustrate the integrated management of patients with vascular disease in the coronary, subclavian, carotid, renal, and lower-extremity circulations. A 76-year-old man with a history of hypertension, hypercholesterolemia, and tobacco use presented to the hospital with sudden severe pulmonary edema and was referred for cardiac catheterization. Five months earlier, …
Appraisal as Cartography: Cultural Studies in the Archives

Joining interdisciplinary conversations within archival appraisal theory, this article asks 1) how does a cultural studies model of appraisal re-imagine the documentary record for institutional archives, and 2) what are the methodological implications of such an approach? In sketching the theoretical overlaps and divergences between archival studies and cultural studies to locate productive tensions between the two disciplines, this article offers a three-pronged approach to appraisal trained on everyday culture and experience. At stake in broadening current appraisal standards are the politics of institutional memory and the limits of archival responsibility.
A Rapid Accurate Electrochemical Method for Serum Uric Acid

Abstract An electrochemical technique for the rapid clinical analysis of serum uric acid is described. This method, in contrast to the widely used phosphotungstate and uricase methods, requires no sample manipulation and uses no reagents. Uric acid concentration is read out digitally in four seconds.
Origin and Significance of Tube Structures in Neoproterozoic Post-glacial Cap Carbonates: Example from Noonday Dolomite, Death Valley, United States

Abstract The Neoproterozoic Noonday Dolomite (Death Valley, USA), a post-glacial cap carbonate, contains closely packed, meter-long, cm-wide, tube-like structures that define the vertical accretion direction. Similar tubestones are known from post-glacial cap carbonates in Namibia and Brazil. In vertical cross section, the tubes average 2 cm in diameter, pinch and swell greatly along their length, may bifurcate and coalesce, and are filled with brown laminated micrite/microspar where best preserved. The tubes do not root or terminate in a particular layer and are randomly distributed where present. The laminated host rock is composed of an early lithified, microclotted fabric with framework void space filled with sparry dolomite cement. The contact between the tube fill and the host rock is diffuse and feathered; commonly, wisps of laminated host rock cross the tube fill and bridge between adjacent stromatolitic structures, compartmentalizing the tubes. The tubes likely result from the contemporaneous int...
Molecules: Rigid/Floppy or Solid/Liquid?

Nearly-rigid molecules and clusters are identified with solid-like systems and very nonrigid molecules and clusters, with liquid-like counterparts. Evidence from analytic theory and simulations is building to indicate that the solid and liquid forms of clusters may coexist in thermodynamic equilibrium over a sharply-bounded range of temperature. The investigation of analogous behavior in molecules, particularly in molecules with high vibrational excitation, has not gone so far but liquid-like small polyatomic molecules are now conceivable. Both solid and liquid “phases” of clusters and of small polyatomics may well be observable, particularly of clusters.
Lower bounds in distributed computing

Distributed computing is the study of achieving cooperative behavior between independent computing processes with possibly conflicting goals. Distributed computing is ubiquitous in the Internet, wireless networks, multi-core and multi-processor computers, teams of mobile robots, etc. In this thesis, we study two fundamental distributed computing problems, clock synchronization and mutual exclusion. Our contributions are as follows. (1) We introduce the gradient clock synchronization (GCS) problem. As in traditional clock synchronization, a group of nodes in a bounded delay communication network try to synchronize their logical clocks, by reading their hardware clocks and exchanging messages. We say the distance between two nodes is the uncertainty in message delay between the nodes, and we say the clock skew between the nodes is their difference in logical clock values. GCS studies clock skew as a function of distance. We show that surprisingly, every clock synchronization algorithm exhibits some execution in which two nodes at distance one apart have Ω( logDloglog D ) clock skew, where D is the maximum distance between any pair of nodes. (2) We present an energy efficient and fault tolerant clock synchronization algorithm suitable for wireless networks. The algorithm synchronizes nodes to each other, as well as to real time. It satisfies a relaxed gradient property. That is, it guarantees that, using certain reasonable operating parameters, nearby nodes are well synchronized most of the time. (3) We study the mutual exclusion (mutex) problem, in which a set of processes in a shared memory system compete for exclusive access to a shared resource. We prove a tight Ω(n log n) lower bound on the time for n processes to each access the resource once. Our novel proof technique is based on separately lower bounding the amount of information needed for solving mutex, and upper bounding the amount of information any mutex algorithm can acquire in each step. We hope that our results offer fresh ways of looking at classical problems, and point to interesting new open problems. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)
Stuck in School: How Social Context Shapes School Choice for Inner-City Students.

BackgroundHigh school choice policies attempt to improve the educational outcomes of poor and minority students by allowing access to high school beyond neighborhood boundaries. These policies assu...
Some Cell Behavior is Encoded in Proteome Physics

More than half the biomass of a bacterial cell is protein. So, some cell behaviors may arise from protein physics -- folding, aggregation, oxidation, and diffusional transport, for example. We develop simple physical models for how protein physics affects cell growth. Cells are sensitive to temperature. We believe this is because cell's live near protein denaturation temperatures. Cells grow slowly in high salts. We believe this is because osmotic shrinkage of the cell crowds proteins, slowing their diffusional transport. A cell's proteome oxidizes with age. We believe this results in the electrostatic unfolding of high-charge proteins. Reasoning with simple models also gives insights into a cell's energy balance, replication speed, and others.
INTERSENSORY TRANSFER OF TRAINING IN YOUNG CHILDREN.

Despite recent beginnings of experimental work on intersensory learning in children (Birch & Lefford, 1963; Blank & Bridger, 1964). the nature and conditions of such learning remain obscure. An experiment was designed to determine whether pretraining in a visual discrimination task would facilitate learning of an analogous auditory task. A group of 15 preschool children (6 boys, 9 girls), ages 3-3 to 5-1, were trained to respond to a two-light visual stimulus sequence by pushing a butcon corresponding to the color (red or blue) of the initial light. Subsequently they were taught to push the red button in response to a 1000-cps tone, and the blue button in response to the sound of a single door-chime. They were tested on a final task, an auditory analog of the visual prerraining: two-sound auditory sequence, tone and chime in randomly alternating order, with 4 blocks of 20 trials each. The red button was "positive" when the tone was the initial sound; the blue button was "positive" when the chime was the initial sound. A similar group of 22 ( 11 boys, 11 girls) children were given equivalenr experience in the room and were trained to respond to a single light by pushing the button of corresponding color. They also were trained to push the red button in response to the cone and the blue button in response to the chime. They were tested on the same final auditory task. Differences in the two groups on the final task were highly significant (F = 75.48, df = 2/35, p < .001), favoring the group with visual sequence training, indicating significant cross-modal transfer effects. However, when a third group of children were trained to respond positively to the linal light in a two-light sequence, they did nor show evidence of transfer to the auditory task. Thus it appears that intersensory transfer of a learned principle can be demonstrated easily in young children, but char the conditions leading to such transfer are not yet well-formulated. Considerably more research on the developmental aspects of intersensory behavior is needed.
Developmental Effects on Phenolic, Flavonol, Anthocyanin, and Carotenoid Metabolites and Gene Expression in Potatoes

Potato phytonutrients include phenolic acids, flavonols, anthocyanins, and carotenoids. Developmental effects on phytonutrient concentrations and gene expression were studied in white, yellow, and purple potatoes. Purple potatoes contained the most total phenolics, which decreased during development (from 14 to 10 mg g(-1)), as did the activity of phenylalanine ammonia-lyase. The major phenolic, 5-chlorogenic acid (5CGA), decreased during development in all cultivars. Products of later branches of the phenylpropanoid pathway also decreased, including quercetin 3-O rutinoside, kaempferol 3-O-rutinoside, and petunidin 3-O-(p-coumaroyl)rutinoside-3-glucoside (from 6.4 to 4.0 mg g(-1)). Violaxanthin and lutein were the two most abundant carotenoids and decreased 30-70% in the yellow and white potatoes. Sucrose, which can regulate phenylpropanoid metabolism, decreased with development in all cultivars and was highest in purple potatoes. Total protein decreased by 15-30% in two cultivars. Expression of most phenylpropanoid and carotenoid structural genes decreased during development. Immature potatoes like those used in this study are marketed as "baby potatoes", and the greater amounts of these dietarily desirable compounds may appeal to health-conscious consumers.
Xanthoproteic and Indican Studies on the Blood in Renal Insufficiency

In 1924 Becher described the yellow color obtained when nitric acid reacts with phenol derivatives in solution as the xanthoproteic reaction. He noted that a positive reaction results when aromatic amino-acids (tyrosine, tryptophane, and phenyl oxyproprionic acid) and phenols and cresols are present in the circulating blood and body fluids. He also observed that the ammo-acid group is insoluble in ether, and that the phenol group is ether soluble. On this difference, the presence of each group separately in the blood could be determined by hydrolysis of the serum and extraction with ether. Normal value for the xanthoproteic reaction done on whole serum without preliminary hydrolysis and ether extraction was given by Becher as 25. This figure represented a measure of the percentage of color found in a positive test by comparison with an 0.3874 per cent potassium bichromate solution. Impressed by the clinical resemblance of chronic phenol poisoning to uremia, Becher wondered whether many of the symptoms of uremia might be due to retention of intestinal putrefactive products including phenol and indol. This speculation was soon confirmed by finding in uremia positive values for the xanthoproteic reaction which ranged from 83 to 250. Further, in uremia