cssi/SciSciGPT-SciSciNet huggingface dataset:
On the Estimation Problem of Mixing/Pair Formation Matrices with Applications to Models for Sexually-Transmitted Diseases

A problem of considerable importance lying at the interface of social dynamics, demography, and epidemiology is determining and modeling who is mixing with whom. In this article we describe a general approach, using nonlinear mixing matrices, for modeling the process of pair-formation in heterogeneous populations. Determining who is mixing with whom is complicated by a variety of factors, including the problem of denominators, which is, in our context, equivalent to the nonexistence of closely interacting social/sexual networks. We describe the use of a mark-recapture model for estimating the sizes of the missing link, that is, the size of the population having sexual contact with a specified population and hence at risk for sexually-transmitted diseases. The need to estimate the size of the sexually-active subset before estimating the size of the population at risk introduces extra variability into the problem. An estimator of the variance of the estimated size of the population at risk that accounts for this extra variability and an expression for the bias of such an estimator have been derived. We illustrate our results with data collected from a population of university undergraduates, and make use of our axiomatic modeling approach for mixing/pair formation to compute specific mixing matrices. Complete details of this work will be published elsewhere.
Regulation of Pituitary Growth and Prolactin Gene Expression by Estrogen

Prolactin is synthesized and secreted by a morphologically and functionally distinct group of cells in the pituitary gland. The relative abundance and secretory activity of the mammotrophic cells is highly influenced by the prevailing endocrine milieu. Various lines of evidence indicate that estrogen is a major regulator of prolactin synthesis and secretion. In female rats, the sharp rise in serum prolactin levels at puberty and the cyclic release of prolactin is associated with the preovulatory surge of estradiol (1, 2). Administration of estrogen to prepubertal rats leads to increased serum levels of prolactin (3,4). Treatment of rats with estrogens was shown to result in increased pituitary DNA synthesis (5–8), hyperplasia and hypertrophy of mammotrophs (9), increased incorporation of radiolabeled precursors into prolactin (7, 10, 11), and increased cellular content of prolactin messenger RNA (12, 13).
Platelet Function Under Flow

As vertebrates have evolved high-pressure, high-flow circulatory systems, an extraordinarily effective hemostatic system has developed alongside to protect these organisms from hemorrhage. More than a century’s worth of evidence indicates that platelets are the blood cells chiefly responsible for maintaining hemostasis and causing thrombosis. Platelets are geared to monitor vascular integrity and effect hemostasis in the arterial circulation, as injuries to arteries (rather than veins) are much more likely to result in circulatory collapse and death. Furthermore, deployment of the hemostatic mechanism in the setting of vascular disease—particularly that caused by atherosclerosis—is largely responsible for the tremendous disease burden associated with vascular disease, being the culminating event in myocardial infarction and stroke. In this chapter, we review the characteristics of blood flow that influence platelet function and the cellular and molecular determinants that allow the platelets to carry out their hemostatic functions under flow.
Induction in an abstraction space: a form of constructive induction

We report on a learning system MIRO which performs supervised concept formation in an abstraction space. Given a domain theory, the method constructs this abstraction space by deduction over instances, and then performs induction in it rather than the initial space defined by instances alone. It is also possible to regard MIRO as a variant of constructive induction. The Vapnik-Chervonenkis model suggests that learning in an abstraction space can result in a substantial speedup, and we provide empirical studies which validate this proposition. We also show that learning in an abstraction space can reduce the number of false negative and false postive classifications because coincidental patterns are filtered by the deduction process. The method is able to extend an incomplete domain theory represented as at tribute-value pairs with a set of rules that represent a disjunctive concept derived from a batch of training instances.
Are French people white?: Towards an understanding of whiteness in Republican France

Based on ethnographic research of France’s North African second-generation, I bring together literatures on racial formation, whiteness, and race and racism in Europe to discuss how whiteness opera...
Letter to the Editor: Melt rupture unleashed by few chain scission events in fully stretched strands

Entangled melts undergo rupture in startup uniaxial extension beyond a threshold Hencky rate. Contrary to the recent conclusion from Wagner et al. [J. Rheol. 62, 221 (2018)] that chain scission involved in melt rupture is due to an “entropic fracture” mechanism, we assert that such a fast melt extension has caused full stretching in entanglement strands, leading to sufficient enthalpic changes associated with conformational distortions at the bond level. The barrier for bond dissociation can only be lowered by enthalpic intrachain forces. The alternative explanation suggests that the more challenging task is to show how entanglement could lock up during sufficiently fast melt stretching.
Acute Hepatitis A

Several types of viral hepatitis exist including hepatitis A, B, C, D, E, and G. Hepatitis A virus is a virus part of the Picornaviridae family causing 114 million infections worldwide annually. Despite it being a self-limiting systemic disease it presents with a broad manifestation of symptoms, clinical presentation, and complications. Children are more likely to be asymptomatic with adults experiencing symptoms such as jaundice and fatigue leading to possible complications as acute liver failure as age of infection increases. Several methods of vaccination, pre-exposure prophylaxis (PreEP), and postexposure prophylaxis (PeP) for the virus exist.
Police Shootings: Is Accountability the Enemy of Prevention?

Police officers shoot an unarmed man or woman. The victim’s family and community cry out for someone to be held accountable. In minority communities, where a disproportionate number of officer-involved shootings occur, residents suspect that racial animus and stereotypical assumptions about “dangerous black men” played a part. Citizens seek accountability by filing lawsuits and demanding criminal prosecutions. They are usually disappointed: The majority of police-involved shootings are deemed “justified” by police investigators and courts, and no criminal charges are brought. If so, this is the end of the inquiry under current legal standards and there is no accountability. There is also no legal reason to ask why the shooting occurred and how it could have been prevented. This article argues that the current accountability paradigm is hindering genuine progress in decreasing the number of police-involved shootings, including those motivated by racism. We need to look beyond the limited time-frame embraced by the current legal standard and view police-involved shootings as organizational accidents. Borrowing lessons learned from the aviation and healthcare fields, this article urges a prevention-first approach that applies systemic analysis to what are systems problems. In these sectors, investigations of tragic accidents employ Sentinel Event Review, a systems-oriented strategy that looks back to identify all the factors that contributed to the event and looks forward to identify systemic reforms that could mitigate the chance of recurrence. The goal is to create systemic barriers that make it more difficult for sharp-end actors to err or misbehave. I am not arguing that individual police officers should escape responsibility for their actions. But our cur-rent relentless focus on accountability – while an understandable human reaction – has become the enemy of prevention in the very communities that need it most.
Governing Equations for Free Surface Flows

The best working definition of free surface flow is the following: Free surface flow occurs in a deformable solution region whereby the shape and size of the region is part of the solution. Free surface flow can be either steady or unsteady. In the unsteady mode the shape and size of the solution region is known at the initial time but it changes continually as the solution progresses. In the steady mode the boundaries of the solution region are not known and must be found by some technique. The steady problem — and to some extent the unsteady problem — forms a mathematical enigma: To find a solution, the differential equation must have well defined boundary conditions applied to the boundary of the solution region, but how can the conditions be applied if the location of the boundary is not known?
Fault-Tree Based Prevention Analysis of Cyber-Attack Scenarios for PRA Applications

Probabilistic risk assessment (PRA) based on event- and fault-tree analyses has long been a popular and powerful technique for formulating system- and plant-level risk scenarios in high-hazard facilities [1]. Event- and fault-tree-based PRA is commonly performed in the nuclear industry using tools like Systems Analysis Programs for Hands-on Integrity Reliability Evaluation (SAPHIRE) [2] or the Computer Aided Fault Tree Analysis System (CAFTA) [3]. Often, the goal of a PRA effort is to assess the risk of events having high consequences to the public or the environment. In such a case, the fault-tree and event-tree analyses in a PRA mostly focus on initiating events and system and component failures that would result in such consequences. However, a much broader spectrum of consequences is possible in principle from cyber-attack: a computer system could be exposed to an attack that could lead to disruption, financial loss or other damage to the system and its organization. It is not only a major threat for businesses, but has recently impacted infrastructure utilities. In a nuclear power plant, the potential consequences of cyber-attack may range from an inconvenience to unplanned reactor shutdowns or to plant damage, or (in principle) worse; but the low-consequence end of this accident spectrum is not typically addressed using PRA models. Hence it is important to understand better, and minimize the risk of, cyber-attacks in nuclear power plants. The proven fault-tree analysis methodology holds a strong promise of a comprehensive, robust, scalable, and efficient assessment of cyber-attack scenarios in NPPs. This paper presents a fault-tree based formulation for a cyber-attack scenario in a water flow-loop comprised of flow controllers and pumps, controlled via manual controls, wired signals and wireless signals that is susceptible to a cyber-attack. The fault-tree analysis technique is applied to a variety of cyber-attacks that may result in system failure. The analysis provides a comprehensive picture of the attack scenarios and an exhaustive list of attack pathways that are critical for causing system failure, paving the way for formulating strategies of performing cyber-attack prevention analysis.
Der typische deutsche Onlinenutzer

Beim elektronischen Handel wird ein groser Teil des Jahresumsatzes mit dem Endverbraucher im Weihnachtsgeschaft gemacht, also erst in den letzten Wochen des Geschaftsjahres. Das kann man als Indikator dafur werten, dass der elektronische Handel im Internet immer noch von nur wenigen Produktbereichen bestimmt wird: Bucher, CDs, Computerspiele und ahnliche Produkte werden offenbar gern verschenkt.
The Big Deal: Should Libraries Stay or Should Libraries Go?

AbstractThis article examines the history of the Big Deal more than 23 years after the beginning of large journal packages being offered to libraries. This article also examines solutions and alter...
RNA in spinal muscular atrophy: therapeutic implications of targeting.

Spinal muscular atrophy (SMA) is caused by low levels of the Survival Motor Neuron (SMN) protein due to deletions of or mutations in the SMN1 gene. Humans carry another nearly identical gene, SMN2,...
Ultrasound-Guided Transgluteal Sciatic Nerve Block for Gluteal Procedural Analgesia.

Abstract Background Adequate analgesia is difficult to achieve in patients with an abscess requiring incision and drainage (I&D). There has been a recent increase in regional anesthesia use in the emergency department (ED) to aid in acute musculoskeletal pain relief. Specifically, transgluteal sciatic nerve (TGSN) block has been used as an adjunct treatment for certain chronic lumbar and lower extremity pain syndromes in the ED. Case Report A 21-year-old woman presented to the ED with a painful gluteal abscess. The pain was so severe that the patient barely tolerated light palpation to the abscess area. Using dynamic ultrasound guidance, a TGSN block was performed with significant pain reduction. Ultrasonographic confirmation of abscess was obtained followed by definitive I&D. She was discharged from the ED and her incision site was healing well at the time of follow-up. Why Should an Emergency Physician Be Aware of This? Abscess I&D is a common procedure in the ED. Procedural analgesia for I&D can be difficult to obtain. We describe the TGSN block as an additional analgesic option to be used for procedural analgesia. The use of regional anesthesia has the potential to decrease unwanted and at times dangerous side effects of opiate use and resource utilization of procedural sedation while optimizing patient comfort.
Caprica Energy and its Choices

Jane Barrow, CEO of Caprica Energy, must recommend to the board which of three potential "unconventional" natural-gas development sites in different parts of the United States the company should pursue. The case takes place in January 2011, when the "low-hanging fruit" of natural-gas production in the United States had essentially been picked. All three of the potential sites (shale, coalbed methane, and tight sands) would require hydraulic fracturing, a process of removing gas that was formerly considered inaccessible by injecting water and chemicals into the ground. Because of emerging concerns about the potential harm "fracking" can do to drinking water, Barrow must not only analyze which site might be most profitable but also what the potential risks to the environment and area residents might be. Excerpt UVA-QA-0765 Rev. Jan. 10, 2014 CAPRICA ENERGY AND ITS CHOICES As she got off the phone with Milo Peterson at the Geology and Science Institute, Jane Barrow, CEO of Caprica Energy, tried to reconcile the information she had just received with a conversation she had had earlier in the week. In that previous conversation, Barrow had spoken with Douglas Brown, a manager at a petroleum-industry organization, as she tried to finalize her thoughts on an impending decision. To momentarily distract herself, Barrow looked at the pile of papers and geographical charts on her desk. They contained information and analysis of the various options her independent natural-gas and oil company was faced with as it looked to expand its resources and increase production. Barrow's job over the next 48 hours was to prepare a recommendation for the company's board of directors. Caprica had three development possibilities, each with its own potential risks and rewards, and Barrow and company management, as part of their analysis and presentation, had to rate the three possibilities for extracting what was known as unconventional gas: shale, coal bed methane, and tight sands. It was January 2011, and the “low-hanging fruit” of natural-gas production in the United States had essentially already been picked. Caprica, like many other oil and natural-gas companies, was now considering expanding its use of hydraulic fracturing, also referred to as “fracking” or “frac'ing” to identify and develop gas supplies that formerly were considered inaccessible. . . .
Developmental Hazard of Environmentally Persistent Free Radicals and Protective Effect of TEMPOL in Zebrafish Model.

Environmentally persistent free radicals (EPFRs) can be detected in ambient PM2.5, cigarette smoke, and soils and are formed through combustion and thermal processing of organic materials. The hazards of EPFRs are largely unknown. In this study, we assess the developmental toxicity of EPFRs and the ability of TEMPOL (4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl) to protect against such hazards using zebrafish embryos. Particles containing EPFRs were acquired by dosing dichlorobenzene (DCB) vapor on the Cab-o-sil/5% CuO particles at 230 °C in vacuo (referred to as DCB-230). The particles were suspended in ultrapure water to make 1 mg/mL of stock solution from which series dilution was undertaken to obtain 10, 20, 30, 40, 50, 60, 80, and 100 µg/mL final test solutions, which were then placed in individual wells with a 4 h postfertilization (hpf) zebrafish embryo. Plates were run in duplicate to obtain a sample size of 24 animals per concentration; 12 embryos were exposed per concentration per plate. Statistical analysis of the morphology endpoints was performed. We investigated overt toxicity responses to DCB-230 in a 22-endpoint battery that included developing zebrafish from 24–120 hpf. Exposure to concentrations greater than 60 µg/mL of DCB-230 induced high mortality in the developmental zebrafish model. Exposure to EPFRs induced developmental hazards that were closely related to the concentrations of free radicals and EPFRs. The potential protective effects of TEMPOL against EPFRs’ toxicity in zebrafish were investigated. Exposure to EPFRs plus TEMPOL shifted the concentration to an induced 50% adverse effect (EC50), from 23.6 to 30.8 µg/mL, which verifies TEMPOL’s protective effect against EPFRs in the early phase of zebrafish development.
Abstract SP143: Advancing Cancer Research During Challenging Times

The impact of the COVID-19 pandemic on care for people with cancer and the conduct of cancer research have been significant and will be evident for many years to come. While the National Cancer Institute (NCI) has brought to bear considerable expertise and capabilities to respond to the pandemic, our top priority remains advancing cancer research. The NCI budget, activities in response to the pandemic, breast cancer research advances, and the vision for cancer clinical trials will be discussed. Citation Format: N Sharpless. Advancing Cancer Research During Challenging Times [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP143.
Computational Diagnostics of GBM Tumors in the Era of Radiomics and Radiogenomics

Machine learning (ML) integrated with medical imaging has introduced new perspectives in precision diagnostics of GBM tumors, through radiomics and radiogenomics. This has raised hopes for developing non-invasive and in-vivo biomarkers for prediction of patient survival, tumor recurrence, or molecular characterization, and therefore, encouraging treatments tailored to individualized needs. Characterization of tumor infiltration based on pre-operative multi-parametric magnetic resonance imaging (MP-MRI) scans would help in predicting the loci of future tumor recurrence, and thereby aiding in planning the course of treatment for the patients, such as increasing the resection or escalating the dose of radiation. Specifying molecular properties of GBM tumors and prediction of their changes over time and with treatment would help characterize the molecular heterogeneity of a tumor, and potentially use a respective combination treatment. In this article, we will provide examples of our work on radiomics and radiogenomics, aiming to offer personalized treatments to patients with GBM tumors.
Parallels between the extracellular matrix roles in developmental biology and cancer biology.

Abstract Interaction of a tumor with its microenvironment is an emerging field of investigation, and the crosstalk between cancer cells and the extracellular matrix is of particular interest, since cancer patients with abundant and stiff extracellular matrices display a poorer prognosis. At the post-juvenile stage, the extracellular matrix plays predominantly a structural role by providing support to cells and tissues; however, during development, matrix proteins exert a plethora of diverse signals to guide the movement and determine the fate of pluripotent cells. Taking a closer look at the communication between the extracellular matrix and cells of a developing body may bring new insights into cancer biology and identify cancer weaknesses. This review discusses parallels between the extracellular matrix roles during development and tumor growth.
Role of Dendritic Cells in Response to Biomaterials

The foreign body reaction accompanying implantation of bulk biomaterials into mammalian systems has been extensively investigated, with emphasis on the elucidation of the role macrophages play in this immune response. While dendritic cells (DCs) have been shown to also persist at the implant site, their function in the process is still not completely clear. This chapter discusses the immuno-biology of DCs and highlights the current understanding of DC–biomaterial interactions in vitro and in vivo.
High School Advanced Placement and Student Performance in College: STEM Majors, Non-STEM Majors, and Gender Differences:

Background/ContextThe past few decades have seen an explosive growth in high-school student participation in the Advanced Placement program® (AP), with nearly two million exams completed in 2011. T...
Challenges in Research in Nutritional Epidemiology

Much has been written about the practice and challenges of research in nutritional epidemiology. For general details concerning this topic, the reader is referred to existing and extensive source materials, including Design Concepts in Epidemiology, edited by Margetts and Nelson [1] and Nutritional Epidemiologyby Willett [2]. These books provide myriad technical details on the goals of nutritional epidemiology and the conduct and interpretation of studies, with discussion of potential pitfalls. This chapter focuses on two issues that are particularly challenging in nutritional epidemiology: (1) how to find out what people eat, and (2) how to think about the effect of diet on health.
The Difficulty in Separating Sisters

The separation of the tightly associated sister chromatids during the anaphase step of cell division is an intricately orchestrated event. Orr-Weaver, in her Perspective, discusses new findings by Zou et al . in this issue that reveal the underlying molecular machinery involved. A protein called a separin, Esp1, is held in check by a securin, which in humans turns out to be the protein encoded by PTTG, an oncogene. Once released from its complex with securin, Esp1 cleaves off a subunit from the cohesin complex that is responsible for keeping the sister chromatids together. Orr-Weaver points out the intriguing possibility that in some tumors, mutation of PTTG may result in abnormal separation of sister chromatids and chromosome instability.
Evaluation of an Anaerobic Granule Biosensor for Upset Early Warning Detection

In this study a porous pot reactor was used to simulate an activated sludge stage and an anaerobic granule biosensor (AGB), as an upset early warning system for activated sludge treatment process, was configured in a down-flow mode with a side-stream of the influent wastewater fed to the top. The hydraulic retention time (HRT) for the porous pot and AGB systems was 12 hours and 6 hours, respectively. The influent was made up of synthetic wastewater. In the first group of toxic loading tests, the prepared cupric chloride solutions were separately injected into both the porous pot and AGB systems at six different concentrations (5, 10, 15, 20, 30, and 45mg Cu/L), and phenol solutions were used at four different concentrations (10, 20, 30, and 45mg phenol/L) in the second group of toxic loading tests. In addition, a control study was included for reference. The porous pot reactor and AGB were monitored for pH, ORP, COD, solids, and ammonia concentrations following a simulated toxic event. The COD removal efficiency of porous pot system decreased dramatically in response to the addition of Cu and phenol. The greatest decrease in COD removal efficiency was from 92% to 52% at a Cu concentration of 30 mg/L, and was from 98% to 76% at a phenol concentration of 45mg/L. The longest time of COD removal efficiency continuous decreasing was 23 hours at a Cu concentration of 45 mg/L, and 7 hours at a phenol concentration of 10mg/L. Similar to the response in COD removal, the ammonia removal efficiency decreased significantly after the Cu shock loading. As the porous pot reactor was challenged with the Cu or phenol shock load, the AGB received an equivalent dose. The most sensitive parameter reflecting the toxic shock load in the AGB was the ORP. The ORP changed more rapidly and uniformly than the pH over both the range of Cu concentrations and phenol concentration tested. The shortest response time to
Multiplicative Spatio-Temporal Models For Remotely Sensed Normalized Difference Vegetation Index Data

Vegetation forecasting is closely tied to many important international concerns, including: monitoring the impacts of global climate change and energy usage, managing the consumption of natural resources, predicting the spread of invasive species, and protecting endangered species. In light of these issues, this article develops vegetation forecasting models for normalized difference vegetation index (NDVI) data recorded by remote sensing via satellites in East Africa. Spatio-temporal auto-regressive moving average (STARMA) is a class of models that can be used in monitoring and forecasting, but it must be modified for highly seasonal processes with temporal trends. We propose to use multiplicative STARMA models to estimate and forecast NDVI values for sub-regions that have previously been detected to have statistically significant temporal trends. For illustration, we select a few East African sub-region’s NDVI series to apply the proposed models and demonstrate the advantages over traditional modeling techniques.
Face mosaicing for pose robust video-based recognition

This paper proposes a novel face mosaicing approach to modeling human facial appearance and geometry in a unified framework. The human head geometry is approximated with a 3D ellipsoid model. Multi-view face images are back projected onto the surface of the ellipsoid, and the surface texture map is decomposed into an array of local patches, which are allowed to move locally in order to achieve better correspondences among multiple views. Finally the corresponding patches are trained to model facial appearance. And a deviation model obtained from patch movements is used to model the face geometry. Our approach is applied to pose robust face recognition. Using the CMU PIE database, we show experimentally that the proposed algorithm provides better performance than the baseline algorithms. We also extend our approach to video-based face recognition and test it on the Face In Action database.
The effects of He on ablation and inductively coupled plasma environment in ultra-violet, nanosecond laser ablation inductively coupled plasma mass spectrometry

Abstract The effects of helium gas on ablation and ICP processes were investigated. Differences in the size, shape, and abundance of aerosol particles generated in argon and helium atmosphere were studied off-line using SEM imaging of aerosol particles impacted on polycarbonate filter disks. In general, ablation in helium generated fewer large particles, and larger, more densely-packed soft agglomerates. However, corresponding changes in the ion densities in the ICP, observed in high-resolution images obtained using LIF, were not always predictable. In all cases, higher He/Ar ratios led to lower ion densities in the ICP. This effect was attributed to increased rates of off-axis diffusion at higher He/Ar ratios. Differences in the ion densities produced during ablation in argon vs helium were highly dependent on sample type, the axial position of vaporization, and the He/Ar ratio. There was evidence that vaporization efficiencies of soft agglomerates were less affected than micron-sized particles by particle acceleration at higher He/Ar ratios.
Regional Cerebellar Volume and Cognitive Function From Adolescence to Late Middle Age

Cerebellar morphology and function have been implicated in a variety of developmental disorders, and in healthy aging. Though recent work has sought to characterize the relationships between volume and age in this structure during adolescence, young, and older adulthood, there have been no investigations of regional cerebellar volume from adolescence through late middle age. Middle age in particular, has been largely understudied, and investigating this period of the lifespan may be especially important for our understanding of senescence. Understanding regional patterns of cerebellar volume with respect to age during this portion of the lifespan may provide important insight into healthy aging and cognitive function as well as pathology from adolescence into later life. We investigated regional cerebellar volume using a highly novel lobular segmentation approach in conjunction with a battery of cognitive tasks in a cross-sectional sample of 123 individuals from 12 to 65 years old. Our results indicated that regional cerebellar volumes show different patterns with respect to age. In particular, the more posterior aspect of the neocerebellum follows a quadratic “inverse-U” pattern, while the vermis and anterior cerebellum follow logarithmic patterns. In addition, we quantified the relationships between age and a variety of cognitive assessments and found relationships between regional cerebellar volumes and performance. Finally, exploratory analyses of sex differences in the relationships between regional cerebellar volume, age, and cognition were investigated. Taken together, these results provide key insights into the development and aging of the human cerebellum, and its role in cognitive function across the lifespan.
Playful Ethnography: Chinua Achebe's Things Fall Apart and Nigerian Education

This paper looks to the critical and popular reception of Chinua Achebe’s first novel Things Fall Apart as an authentic text offering an “insider” perspective on Igbo culture. Drawing from the nature of small magazines and university publications in 1950s Nigeria, this paper suggests that early Nigerian authors like Achebe were educated and began writing in a culture that valued play. These early publications express multiple uses of the texts students read in colonial school, and I read Achebe’s novel as an extension of this playfulness. Although it is generally seen as an example of the empire “writing back,” I argue that Things Fall Apart actually takes ethnographic accounts of Nigerian village life—especially G.T. Basden’s Niger Ibos and C.K. Meek’s Law and Authority in a Nigerian Tribe —and uses them in the ways that Achebe and others developed while writing in the earlier small magazines. Seeing Achebe’s work in this light allows for a complex view of the novel’s presentation of Igbo life, and I claim that such a reading comments upon the relationship between colonial education, ethnographic description, and first-wave Nigerian literary production.
Cell damage excites nociceptors through release of cytosolic ATP

The release of cytosol from damaged cells has been proposed to be a chemical trigger for nociception. K(+), H(+), adenosine triphosphate (ATP), and glutamate are algogenic agents within cytosol that might contribute to such an effect. To examine which, if any, compounds in cytosol activate ion channels on nociceptors, we recorded currents in dissociated nociceptors when nearby skin cells were damaged. Skin cell damage caused action potential firing and inward currents in nociceptors. Extracts of fibroblast cytosol did the same. Virtually all response to extract and cell killing was eliminated by enzymatic degradation of ATP or desensitization or blockade of P2X receptors, ion channels that are activated by extracellular ATP. Thus, if cytosol provides a rapid nociceptive signal from damaged tissue, then ATP is a critical messenger and P2X receptors are its sensor.
Comparative relationship between serum gastrin concentration and gastric acid output

Gastric hydrochloric acid output and serum gastrin concentrations were compared to determine whether there was any correlation between circulating serum gastrin levels and acid output in the fasting, interdigestive state of the dog, miniature pig and monkey (Macaca mulatta). No correlation was seen in any species except in the anesthetized, vagotomized dog. In the monkey and miniature pig, interdigestive secretion is predominantly controlled by direct vagal stimulation of the parietal cell. Conversely, in the anesthetized, vagotomized dog, acid secretion may be primarily under gastrin control.
Sub-second mode measurement of fibers using C 2 imaging

We implement cross-correlated imaging in the frequency domain (fC2) in order to reconstruct different modes propagating in a multi-mode optical fiber, and measure their relative powers. Our system can complete measurements in under a second (950 ms), with a maximum signal to noise ratio of 25 dB. The system is capable of group-delay temporal resolution as high as 720 fs, and this number can be tailored for a variety of modal discrimination levels by choice of apodization functions and effective bandwidths of the tunable source we use. Measurements are made on a double-clad test fiber to demonstrate simultaneous reconstruction of six guided modes. Finally, the system is used to optimize alignment into the fiber under test and achieve mono-mode purity > 95%, underscoring the utility of fC2 imaging for near-real-time modal content analysis.
Air-flow geometry in air sparging of fine-grained sands

Laboratory visualization experiments in fine- to very fine-grained sands (grain diameter <0.21 mm) re- veal a previously unrecognized air-flow geometry. This air-flow geometry is termed "chamber flow" and is char- acterized by: (1) a significant horizontal component, (2) pervasive air-flow coverage within a region demarcated by a distinct, irregular boundary, and (3) the presence of predominantly vertical inlet and outlet channels. The at- tributes of chamber flow differ significantly from chan- nelized flow and pervasive/bubbly flow, which occur at larger grain sizes and have been described in the litera- ture by several researchers. Previous research, which in- dicates a dramatic increase in contaminant removal time in sediments <0.2 mm, indirectly corroborates the phe- nomena observed in this study. The extent of sediment column affected by chamber flow of sparge air ranges from 4-54% on an area basis, and is approximately 28% on a volume basis. These values indicate that chamber air flow has the potential to affect a much larger percent- age of the sediment column than either channelized or pervasive/bubbly flow. Because of the irregularity of air- flow chambers, in terms of both form and frequency, a detailed knowledge of stratigraphy is important to maxi- mize air-sparging efficiency at sites where chamber flow is likely to occur. Resume Des experiences de visualisation en laboratoire dans des sables a grains fins a tres fins (diametre des grains inferieur a 0,21 mm) ont mis en evidence une geo- metrie des ecoulements d'air non reconnue auparavant. Cette geometrie des ecoulements d'air est nommee «ecoulement en cavite» et est caracterisee par (1) une
Game-theoretic quorum-based frequency hopping for anti-jamming rendezvous in DSA networks

Establishing communications in a dynamic spectrum access (DSA) network requires the communicating parties to “rendezvous” before transmitting their data packets. Frequency hopping (FH) is an effective rendezvous method that does not rely on a predetermined control channel. Recently, “quorum-based” FH approaches have been proposed for asynchronous rendezvous in DSA networks. These approaches are highly vulnerable to jamming, especially when the attacker is an insider node (i.e., a compromised node). In this paper, we investigate the problem of two secondary users (SUs), a transmitter and a receiver, try to rendezvous in the presence of a third SU acting as a jammer. The jammer is aware of the underlying (quorum-based) rendezvous design. First, we consider the case when all SUs are time-synchronized and are aware of the “rendezvous channel.” We formulate the problem as a three-player game between the transmitter, receiver, and jammer. The transmitter and receiver try to maximize the number of successful rendezvous slots, while minimizing the number of jammed rendezvous slots. The jammer has the opposite objective. We show that this game does not have a pure Nash equilibrium (NE). Accordingly, we formulate a simplified two-player game between the receiver and jammer (assuming a uniform strategy by the transmitter), and derive multiple pure NE strategies. Next, we study the case when the rendezvous channel is unknown and obtain the Bayesian NE. Finally, the asynchronous case is addressed by exploiting the “rotation closure property” of quorum systems. Our numerical experiments show that uncertainty about the transmitter's strategy improves the anti-jamming rendezvous performance. They also show that the rendezvous performance improves if the receiver and jammer are time-synchronized, and also improves if the receiver and jammer have a common guess about the transmitter's strategy.
Characterization of anomaly detection in hyperspectral imagery

Purpose – The paper aims to characterize anomaly detection in hyperspectral imagery.Design/methodology/approach – This paper develops an adaptive causal anomaly detector (ACAD) to investigate several issues encountered in hyperspectral image analysis which have not been addressed in the past. It also designs extensive synthetic image‐based computer simulations and real image experiments to substantiate the work proposed in this paper.Findings – This paper developed an ACAD and custom‐designed computer simulations and real image experiments to successfully address several issues in characterizing anomalies for detection, which are – first, how large size for a target to be considered as an anomaly? Second, how an anomaly responds to its proximity? Third, how sensitive for an anomaly to noise? Finally, how different anomalies to be detected? Additionally, it also demonstrated that the proposed ACAD can be implemented in real time processing and implementation.Originality/value – This paper is the first work...
The importance of physical and biotic scaling to the experimental simulation of a coastal marine ecosystem

A marine microcosm, consisting of a pelagic phase interacting with a benthic phase, is described. Variations in water turnover, turbulence, incident radiation and ratio of pelagic volume to benthic surface area are shown to have significant effects on the behavior of these microcosms. It is argued that the inclusion and accurate simulation of appropriate levels of these variables is important in microcosm studies designed to study the dynamics of natural systems.
Normal-mode splitting and linewidth averaging for two-state atoms in an optical cavity

An investigation of the radiative processes for a collection of N two-state atoms strongly coupled to the field of a high-finesse optical cavity is presented. Observations of the spectral response of the composite system to weak external modulation reveal a coupling-induced normal-mode splitting. Linewidth averaging leads to linewidths below the free-space atomic width.
Circadian clocks, clock networks, arylalkylamine N-acetyltransferase, and melatonin in the retina

Circadian clocks are self-sustaining genetically based molecular machines that impose approximately 24h rhythmicity on physiology and behavior that synchronize these functions with the solar day-night cycle. Circadian clocks in the vertebrate retina optimize retinal function by driving rhythms in gene expression, photoreceptor outer segment membrane turnover, and visual sensitivity. This review focuses on recent progress in understanding how clocks and light control arylalkylamine N-acetyltransferase (AANAT), which is thought to drive the daily rhythm in melatonin production in those retinas that synthesize the neurohormone; AANAT is also thought to detoxify arylalkylamines through N-acetylation. The review will cover evidence that cAMP is a major output of the circadian clock in photoreceptor cells; and recent advances indicating that clocks and clock networks occur in multiple cell types of the retina.
Polyamines and the stimulation of DNA synthesis in chicken embryo fibroblasts by purified multiplication-stimulating activity.

Abstract Multiplication-stimulating activity (MSA), a protein which stimulates DNA synthesis and growth of chicken embryo fibroblasts, was purified from serum-free medium conditioned by the growth of a rat liver cell line. Purified MSA stimulates ornithine decarboxylase (ODC) activity approximately 7-fold when added to cultures of serum deprived chicken embryo fibroblasts. Enzyme activity increases shortly after addition of MSA to the cells, with a peak of activity at 4.5 hours. As cells enter S phase, ODC activity declines rapidly. MSA also stimulates putrescine uptake which coincides closely with the increase in ODC activity. Cycloheximide inhibits both the increase in enzyme activity and in putrescine transport. Treatment of the cells with methyl glyoxal bis (guanylhydrazone) (MGBG), an inhibitor of spermidine and spermine synthesis and function, at the time of MSA addition, drastically inhibits subsequent DNA synthesis and growth of the cell. MGBG inhibition could be partially reversed by the addition of spermidine or spermine (but not putrescine) to the medium. The possible involvement of polyamines in the regulation of DNA synthesis by this purified growth factor is discussed.
Multidimensional behavioral effects of marijuana

Abstract Kelly Thomas H., Richard W. Foltin, Cleeve S. Emurian and Marian W. Fischman: Multidimensional Behavioral Effects of Marijuana. Prog. Neuro-Psychopharmacol. & Biol. Psychiat. 1990, 14 : 885–902. 1. 1. Five groups of three healthy adult male volunteers (n = 15), all reporting occasional, controlled marijuana use, gave written consent and participated in residential studies lasting 6 to 15 days. 2. 2. Subjects smoked marijuana cigarettes (0 1.3 2.3 or 2.7% THC, w/w) at 0945, 1330, 1700 and 2030 every day, and each subject received both active and placebo marijuana cigarettes in 2–5 consecutive day phases, with placebo and active doses presented in an alternating fashion. 3. 3. In comparison with placebo, active marijuana produced a variety of effects on measures of human behavior, including increases in food consumption and errors on psychomotor tasks, decreases in bouts of tobacco-cigarette smoking and verbal interactions and no changes in rates of task performance, time spent under social conditions or social cooperation. 4. 4. Dimensions of human behavior were differentially sensitive to the effects of smoked marijuana. 5. 5. The simultaneous measurement of multiple dimensions of human behavior is a useful procedure for determining dose potency following marijuana administration.
Pitting of a glass-ceramic during polishing with cerium oxide

Abstract The pitting behavior of a transparent spinel-based glass-ceramic polished with a cerium oxide abrasive has been investigated using finishing experiments supported by indentation testing. The pre-ceramed, `green' glass consistently polished to a surface quality of average roughness (Ra)
A sample collector for robotic sample return missions II: Radiation tests

Abstract Sample return from small solar system objects is playing an increasingly important part in solar system exploration. Critical to such missions is a robust, simple, and economic sample collector. We have developed a collector such as this for near-Earth asteroid sample return missions that we have termed the Touch-and-Go Impregnable Pad (TGIP). The collector utilizes a silicone substrate that is pushed into the dust and gravel surface layer of the asteroid. As part of a systematic evaluation of the TGIP, we have investigated the resilience of this substrate to ionizing radiations. Several miniature versions of the collector, containing typically ∼3 g of the collection substrate, were exposed to 0.564 MeV beta particles from a 90 Sr source and a 6 MeV electron beam in a linear accelerator to simulate the wide range of energies of solar and galactic ionizing radiation. Various radiation levels up to eight times greater than expected on a six-year asteroid mission (in the case of beta radiation) and 50 times greater than expected (in the case of the 6 MeV electron radiation) were administered to the substrate. After irradiation, the efficiency of the substrate in collecting samples of mock regolith was compared with that of collectors that had not been irradiated. No difference beyond experimental uncertainty was observed and we suggest that the operational TGIP will not be affected adversely by radiation doses expected during a typical six-year inner solar system mission.
Stability Balls and Students With Attention and Hyperactivity Concerns: Implications for On-Task and In-Seat Behavior

We evaluated the effects of stability balls on in-seat and on-task behavior of students with attention and hyperactivity concerns. A group of 8 students in the 4th and 5th grades was observed 3 times/wk for 12 wk using a single-subject A-B continuous time-series design. We analyzed data collected from standardized measures and classroom observations for mean differences across pre- and postintervention phases. Results of the stability ball intervention revealed increased levels of attention, decreased levels of hyperactivity, and increased time on task and in seat or on ball. Findings from the social validity questionnaire demonstrated that teachers preferred the stability balls over chairs. This study provides additional evidence for the effectiveness of stability balls in the general education classroom for children who exhibit difficulties with attention and hyperactivity.
Herpes simplex Virus dna in normal corneas: Persistence without viral shedding from ganglia

Herpes simplex virus type 1 (HSV-1) DNA has been shown to persist in the cornea not only after inoculation of experimental animals but also in surgical samples from patients with herpes keratitis. The further observation of corneal HSV-1 DNA in subjects without known HSV eye disease prompted the present study of the presence and distribution of HSV-1 in eye bank corneas. Prior to DNA extraction, the corneas were trephined, separating the central and peripheral cornea. With polymerase chain reaction (PCR) for HSV-1 thymidine kinase (TK) and glycoprotein D (gD) gene sequences, we found HSV-1 in 10 of 24 eye bank corneas, from the 4 mm wide corneal rim in 8 eyes and from the 8 mm diameter central cornea in 2 eyes. In 9 subjects, both eyes were assayed, and HSV-1 was detected in 6 subjects. In only one subject was HSV-1 detected in both eyes and in only one subject was HSV-1 detected in the central and peripheral cornea of the same eye. The biological role of HSV-1 DNA corneal sequences is unknown. To investigate this, a rabbit animal model was established by transplantation of corneas containing viral DNA sequences in HSV-1 naive recipients. Followed for 5 months, there was no evidence of sheeding of HSV-1 in the tear film or seroconversion of the recipient rabbits. At the end of this time, HSV-1 DNA was detected in the corneal graft at a similar intensity to the PCR signal from the donor rims.(ABSTRACT TRUNCATED AT 250 WORDS)