cssi/SciSciGPT-SciSciNet huggingface dataset:
Surface Interactions and Confinement of Methane: A High Pressure Magic Angle Spinning NMR and Computational Chemistry Study.

Characterization and modeling of the molecular-level behavior of simple hydrocarbon gases, such as methane, in the presence of both nonporous and nanoporous mineral matrices allows for predictive understanding of important processes in engineered and natural systems. In this study, changes in local electromagnetic environments of the carbon atoms in methane under conditions of high pressure (up to 130 bar) and moderate temperature (up to 346 K) were observed with 13C magic-angle spinning (MAS) NMR spectroscopy while the methane gas was mixed with two model solid substrates: a fumed nonporous, 12 nm particle size silica and a mesoporous silica with 200 nm particle size and 4 nm average pore diameter. Examination of the interactions between methane and the silica systems over temperatures and pressures that include the supercritical regime was allowed by a novel high pressure MAS sample containment system, which provided high resolution spectra collected under in situ conditions. For pure methane, no signif...
Establishing symmetric connectivity in directional wireless sensor networks equipped with \(2\pi /3\) antennas

In this paper, we study the antenna orientation problem concerning symmetric connectivity in directional wireless sensor networks. We are given a set of nodes each of which is equipped with one directional antenna with beam-width $$\theta = 2\pi /3$$ and is initially assigned a transmission range 1 that yields a connected unit disk graph spanning all nodes. The objective of the problem is to compute an orientation of the antennas and to find a minimum transmission power range $$r=O(1)$$ such that the induced symmetric communication graph is connected. We propose two algorithms that orient the antennas to yield symmetric connected communication graphs where the transmission power ranges are bounded by 6 and 5, which are currently the best results for this problem. We also study the performance of our algorithms through simulations.
Tandem Oxidative Dearomatizing Spirocyclizations of Propargyl Guanidines and Ureas

Treatment of propargyl ureas or guanidines with iodosobenzene diacetate results in an oxidative tandem amination/etherification dearomatizing spirocyclization. This transformation leads directly to the complete framework of the Leucetta alkaloids, spirocalcaridine A and B.
Power constrained SiGe/SOI sub 6GHz LNA design analysis and comparison

In this paper, we first analyze an LNA core, cascode structure cut off frequency and power gain relationship with device parameters. Then we discuss the LNA design differences between FET LNA and SiGe LNA during design optimization. SOI floating body FETs have advantages in higher Ft in the optimized current biased region and can offer more design flexibility, while SiGe NPNs need much less trade off room. With this design methodology, we design 5GHz LNAs based on 120nm SOI FET and 0.12um SiGe NPN with 5mA current limitation. The SOI NFET LNA achieves 16dB gain and 1.2dB NF, while SiGe achieves 20dB gain and <1dB NF.
C.I. Lewis: From Conceptual Pragmatism to Contemporary Metaethics

Lewis is known as an epistemologist and logician but not as a value theorist. This chapter argues that Lewis’s contributions to metaethics have been unjustly overlooked. The recovery of Lewis’s metaethics requires situating Lewis as a pragmatist value theorist, and developing four key planks of his value theory. The chapter concludes with explication of why Lewis’s value theory has been forgotten and how it can be used to resolve a debate between cognitivists and emotivists in contemporary metaethics.
Ferro's El otro Joyce: Originals and Copies

This article explores Roberto Ferro’s novel El otro Joyce (2011), a work of translational literature that straddles two languages and two literary traditions. Its protagonist, Jorge Caceres, runs a small business researching patents, missing books, and missing persons. The novel’s plot follows him as he works to solve two mysteries: one related to the search for a first edition of Joyce’s Finnegans Wake, annotated by Jorge Luis Borges, and the second related to the suspicious death of Marcos Almeida, a prominent financier. Much like Finnegans Wake, El otro Joyce is a highly self-conscious narrative teeming with digressions and literary allusions. Caceres’s work is constantly hindered and confused by the appearance of doubles, a theme that relates to the act of translation and also to betrayal, present throughout the novel. Part detective narrative and part historical metafiction, Ferro’s novel is a reflection on the continuing role of Joyce in the Argentine literary tradition—a tradition inseparable from the act of translation.
The Effects of State Higher Education Policies and Institutions on Access by Economically Disadvantaged Students

Do state government policies and institutions promote access to postsecondary education by economically disadvantaged students? I analyze the number of state residents receiving federal Pell grants relative to the college-age population raised in low-income households. Using data for 1993–2008, I estimate separate models for total Pell recipients and for those enrolled in public, private nonprofit, and proprietary institutions. I find consistent evidence that state spending on both need- and merit-based financial aid enhances access by economically disadvantaged students, with the effects of need-based aid being larger and more robust than those of aid based at least in part on merit. I also find that students in states with consolidated governing boards have slightly greater access to public and nonprofit institutions than those with statewide coordinating boards. Enrollment by economically disadvantaged students in the public and proprietary sectors also responds to the opportunity costs of attending college, as measured by the state unemployment rate. I do not find evidence of direct effects from state policies limiting affirmative action, or political elites’ ideology.
It's time for low latency

The operating systems community has ignored network latency for too long. In the past, speed-of-light delays in wide area networks and unoptimized network hard-ware have made sub-100µs round-trip times impossible. However, in the next few years datacenters will be deployed with low-latency Ethernet. Without the burden of propagation delays in the datacenter campus and network delays in the Ethernet devices, it will be up to us to finish the job and see this benefit through to applications. We argue that OS researchers must lead the charge in rearchitecting systems to push the boundaries of low-latency datacenter communication. 5-10µs remote procedure calls are possible in the short term - two orders of magnitude better than today. In the long term, moving the network interface on to the CPU core will make 1µs times feasible.
Investigating the effect of fused deposition modeling processing parameters using Taguchi design of experiment method

Abstract Fused Deposition Modeling (FDM) is an Additive Manufacturing (AM) technique that fabricates parts layer upon layer. The recent development of AM technologies is driving FDM from rapid prototyping to rapid manufacturing. However, building end-user functional parts using FDM proved to be a challenging task, which is due to having many processing parameters that may influence the parts’ quality. It is challenging to use full factorial Design of Experiments (DOE) to investigate the influence when there are many processing parameters, especially when the processing parameters are not expected to behave linearly. In addition, to fully exploit the accurate processing parameters influence a large number of sample sets are required. In this paper, Taguchi’s DOE is used to investigate the main effects of four processing parameters in the FDM process, those are the infill percentage, infill pattern, layer thickness, and extrusion temperature. The processing parameters influence is expressed in terms of the mechanical properties and dimensional accuracy of FDM parts fabricated. The material under interest is PLA filament fabricated using a commercial FDM 3D printer. In the presented work, we used Taguchi’s L9 array that had 9 runs with 3 repeated specimens for each, hence a total of 27 specimens were fabricated using varying processing parameters. The dimensions of the fabricated specimens were compared with the 3D CAD model and then tested according to the ASTM D638 standard. The results showed that for generally better dimensional accuracy, a lower extrusion temperature, smaller layer thickness, lower infill percentage, and hexagonal infill pattern were required. In addition, current FDM fabrication process usually generates parts with larger dimensions as compared to the CAD model. On the other hand, to increase the strength of FDM parts, a higher extrusion temperature, an optimized layer thickness, a triangular infill pattern, and a higher infill percentage are required. Ductility can be improved by switching to rectilinear infill pattern and by increasing the layer thickness.
Effect of Biaxial Orientation on Microstructure and Properties of Renewable Copolyesters of Poly(ethylene terephthalate) with 2,5-Furandicarboxylic Acid for Packaging Application

The cost and availability of 2,5-furandicarboxylic acid (FDCA), a monomer for poly(ethylene 2,5-furandicarboxylate) (PEF), limit the use of PEF as a biobased alternative to poly(ethylene terephthal...
Children with Upper Airway Dysfunction: At Risk of Obstructive Sleep Apnea

Obstructive sleep apnea is characterized by prolonged partial upper airway obstruction or intermittent complete obstruction that disrupts normal ventilation during sleep and alters normal sleep patterns. Patients with obstructive sleep apnea tend to develop neurocognitive, cardiovascular, behavioral, attention issues, and poor academic performance. Therefore, it is essential to diagnose and treat obstructive sleep apnea early and avoid significant and long-lasting adverse outcomes. Most commonly, upper airway obstruction is caused by enlarged lymphoid tissues within the upper airway, and therefore adenotonsillectomy is considered as the first-line treatment of obstructive sleep apnea in children. Fifty to 70% of patients who have obstructive sleep apnea and treated by surgery are not entirely cured on follow-up polysomnography. In light of this, it is recommended that patients with suspected obstructive sleep apnea undergo a thorough evaluation, and all potential risk factors are identified and treated. The purpose of this review is to familiarize pediatricians with developmental, anatomical, and physiological risk factors involved in the development of obstructive sleep apnea. Additionally, we will present an array of evaluation techniques that can offer adequate assessment of the patient's upper airway anatomy and physiology.
Cyclic symmetries of An-quiver representations

Abstract This note contains a combinatorial construction of symmetries arising in symplectic geometry (partially wrapped or infinitesimal Fukaya categories), algebraic geometry (derived categories of singularities), and K -theory (Waldhausen's S-construction). Our specific motivation (in the spirit of expectations of Kontsevich) is a combinatorial construction of categorical quantizations of Lagrangian skeleta of symplectic manifolds. The main result of this paper gives an immediate solution in the one-dimensional case of ribbon graphs.
Distributed biomass supply chain cost optimization to evaluate multiple feedstocks for a biorefinery

Abstract Conventional practices of siting all biomass preprocessing operations at the biorefinery is widely believed to be the most cost-effective solution for feedstock supply because of economies of scale. However, biomass preprocessing operations could be decentralized by moving the preprocessing operations to distributed biomass preprocessing centers, also known as “depots” located near biomass sources. This study presents a comparative case study with multiple biomass resources to analyze biorefinery feedstock supply logistics designs having distributed depots and a primary depot co-located with the biorefinery. A mixed-integer linear programming model was developed to simultaneously optimize feedstock sourcing decisions, and optimal preprocessing depot locations and size, utilizing biomass resources from agricultural residue, energy and municipal solid waste to meet carbohydrate specifications and feedstock demand for a biochemical conversion process. Results from a case study in the US showed that a biorefinery could increase its feedstock supply draw area and supply volume by 57.3%, 177.4% respectively without increasing the feedstock delivered cost by adopting distributed depot-in the feedstock supply chain design. A distributed-depot-based supply chain can be more economical by selecting optimal mix of biomass resource, optimal siting and depot scales during feedstock supply chain design. The findings from this study indicate that a biorefinery can utilize dynamic blending to meet the feedstock quality specifications as well as larger supply radius in the distributed depot-based supply chain design to access more available biomass to handle potential feedstock supply uncertainty.
Acute Abdominal Series: The Views and What They Show

Acute abdominal series is a set of abdominal radiographs obtained to evaluate bowel gas. The usual projections for this series are AP supine view (to estimate the amount of bowel gas or possible distension), PA erect view (to assess air-fluid levels), and PA erect chest radiograph (to rule out free air) . If the patient cannot tolerate upright position, left lateral decubitus position can substitute.
Switchable electrical conductivity in a three-dimensional metal–organic framework via reversible ligand n-doping

Redox-active metal-organic frameworks (MOFs) are promising materials for a number of next-generation technologies, and recent work has shown that redox manipulation can dramatically enhance electrical conductivity in MOFs. However, ligand-based strategies for controlling conductivity remain under-developed, particularly those that make use of reversible redox processes. Here we report the first use of ligand n-doping to engender electrical conductivity in a porous 3D MOF, leading to tunable conductivity values that span over six orders of magnitude. Moreover, this work represents the first example of redox switching leading to reversible conductivity changes in a 3D MOF.
Neural-network based classification of non-adherent cancer cells using Label free Quantitative Phase Imaging data (Conference Presentation)

We apply label-free imaging using digital holographic microscopy to analyze different cancer cell lines. Separation of cell lines based on extraction of amplitude and phase map variations along with post-processed, population specific parameters, was accomplished using machine learning. These data are used to train a neural network algorithm that attains accurate discrimination of non-adherent cancer cells.
Performance Analysis of Message Dissemination Techniques in VANET using Fog Computing.

Vehicular Ad-hoc Networks (VANET) is a derived subclass of Mobile Ad-hoc Networks (MANET) with vehicles as mobile nodes. VANET facilitate vehicles to share safety and non-safety information through messages. Safety information includes road accidents, natural hazards, roadblocks, etc. Non-safety information includes tolling information, traveler information, etc. The main goal behind sharing this information is to enhance road safety and reduce road accidents by alerting the driver about the unexpected hazards. However, routing of messages in VANET is challenging due to packet delays arising from high mobility of vehicles, frequently changing topology and high density of vehicles, leading to frequent route breakages and packet losses. This report summarizes the performance analysis of safety and non-safety message dissemination techniques in VANET based on the fog computing technique. Three main metrics to improve the performance of message dissemination are: 1) delay, 2) probability of message delivery, and 3) throughput. Analysis of such metrics plays an important role to improve the performance of existing message dissemination techniques. Simulations are usually conducted based on the metrics using ns-2 and Java discrete event simulator. The above three performance metrics and results published in literature help one to understand and increase the performance of various message dissemination techniques in a VANET environment.
Isotropic 3D Super-resolution Imaging with a Self-bending Point Spread Function

We introduce a self-bending point spread function (SB-PSF) based on Airy beams for three-dimensional (3D) super-resolution fluorescence imaging. We designed a side-lobe-free SB-PSF for the incoherent fluorescence emission and implemented a two-channel detection scheme for the SB-PSF to enable unambiguous 3D localization of fluorescent molecules. The lack of diffraction and the propagation-dependent lateral bending make the SB-PSF ideal for precise 3D localization of molecules over a large imaging depth. Using this SB-PSF, we demonstrated super-resolution imaging with isotropic localization precisions of 10-15 nm in all three dimensions over a 3 μm imaging depth without sample scanning.
Non‐necrotizing Granulomatous Pneumonitis and Chronic Pleuritis in Soldiers Deployed to Southwest Asia

Aims Reports of respiratory illnesses among soldiers returning from Southwest Asia have been described. During deployment to Southwest Asia, soldiers are exposed to various respiratory hazards, including dust storms, smoke from burn pits and industrial air pollutants. A few studies have reported increased rates of constrictive bronchiolitis and asthma in these patients. We sought to expand upon the pathological findings in this cohort. Methods and results Lung biopsies from veterans of Southwest Asia were identified and re-reviewed. All patients had undergone pulmonary function tests and chest high-resolution CT imaging with no significant findings. Overall, 59 patients with a history of inhalational exposure to at least one of the following were identified: smoke from burn pit, dust storm and sulphur plant fire. Samples included video-assisted thoracoscopic lung biopsies (57 of 59, 96.6%) and cryobiopsies (two of 59, 3.4%). Patients were predominantly male (54 of 59, 91.5%) with an age range of 24-55 years (mean and median = 35). Non-necrotising, poorly formed granulomas were identified in 22 cases (22 of 59, 37.2%). The granulomas were mainly bronchiolocentric and were associated with chronic lymphoplasmacytic bronchiolitis, similar to hypersensitivity pneumonitis (HP). Pleural reaction in the form of focal chronic lymphocytic pleuritis and/or focal pleural adhesions were seen in 43 of 57 (75.4%) biopsies. Conclusions To our knowledge, this is the first study to report pleural reaction as well as features of HP in this population, suggesting that pleural reaction and HP may be part of the spectrum of Southwest Asia deployment-related lung diseases.
Bottomland hardwood forest growth and stress response tohydroclimatic variation: Evidence from dendrochronology andtree-ring δ 13 C values

Abstract. Wetland forests around the world have been reduced to a small proportion of their original expanse due to changing climatic conditions and intensification of human land use activities. As a case in point, the Columbia bottomland hardwood forests along the Brazos-Colorado Coastal Basin on the Gulf coast of Texas are currently threatened by an increasingly erratic hydroclimate in the form of both extreme floods as well as droughts, and by urban expansion. In this study, we use dendrochronology and tree-ring carbon isotopes to understand the effect of changing hydroclimatic conditions on the functional attributes of these forests. We examined tree-rings of Quercus nigra at four sites within the Columbia bottomlands, of which one site experiences frequent and prolonged flooding, while the other three are less flood-prone. The objectives of this study were to: (i) understand the impact of hydroclimatic variation on growth rates using tree-ring width analysis, (ii) assess the magnitude of physiological stress inflicted by extreme hydroclimatic conditions using tree-ring δ13C measurements, and (iii) evaluate the relationship between physiological stress and growth inhibition. Growth rates across the landscape were influenced most strongly by mid-growing season climate, while early-growing season climate inflicted the greatest physiological stress. Neither growth inhibition nor changes in δ13C values were observed in trees at the wetter site under extreme hydrologic conditions such as droughts or floods. In addition, trees at the wet site were less sensitive to precipitation and showed no response to higher temperatures. In contrast, trees of the three drier sites experienced growth inhibition and had higher tree-ring δ13C values during dry periods. Our results indicate higher physiological resilience in trees growing under wetter conditions. Management and conservation strategies dependent on site-specific conditions are critical for the health of these wetland forests under a rapidly changing hydroclimate. This study provides the first dendrochronological baseline for this region and thresholds of optimum conditions for the growth and health of these forests which can assist management decisions such as streamflow regulation and conservation plans.
The distribution of primes and an introduction to class field theory

We will consider several situations in which the primes of a number field are mapped in a natural way into a finite abelian group. In each case they turn out to be distributed uniformly (in some sense) among the members of the group; in particular each group element is the image of infinitely many primes. Except in certain special cases, however, the proof of this depends upon facts from class field theory which will not be proved in this book. Thus this chapter provides an introduction and motivation for class field theory, which is the study of the abelian extensions of a number field, by showing how the existence of certain extensions leads to uniform distribution results.
Severe Hypoglycemia and Risk of Falls in Type 2 Diabetes: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE Hypoglycemia has been postulated to contribute to falls risk in older adults with type 2 diabetes. However, few studies have prospectively examined the association between severe hypoglycemia and falls, both important causes of morbidity and mortality. RESEARCH DESIGN AND METHODS We conducted a prospective cohort analysis of participants from the Atherosclerosis Risk in Communities (ARIC) Study with diagnosed diabetes at visit 4 (1996–1998). Episodes of severe hypoglycemia requiring medical treatment were identified using International Classification of Diseases, Ninth Revision, codes from hospitalizations, emergency department visits, and ambulance calls; total falls were identified from medical claims using E-codes from 1996 to 2013. Secondary analyses examined hospitalized falls and falls with fracture. We calculated incidence rates and used Cox regression models to evaluate the independent association of severe hypoglycemia with falls occurring after visit 4 through 2013. RESULTS Among 1,162 participants with diabetes, 149 ever had a severe hypoglycemic event before baseline or during the median of 13.1 years of follow-up. The crude incidence rate of falls among persons without severe hypoglycemia was 2.17 per 100 person-years (PY) (95% CI 1.93–2.44) compared with 8.81 per 100PY (6.73–11.53) with severe hypoglycemia. After adjustment, severe hypoglycemia was associated with a more than twofold higher risk of falls (hazard ratio 2.23, 95% CI 1.61–3.07). Associations were consistent in subgroups defined by age, sex, race, BMI, duration of diabetes, or functional difficulty. CONCLUSIONS Severe hypoglycemia was associated with a substantially higher risk of falls in this community-based population of adults with diabetes. Fall risk should be considered when individualizing glycemic treatment in older adults. Assessing hypoglycemia history and future hypoglycemia risk could also improve multifactorial fall prevention interventions for older adults with diabetes.
The obesity gap: An investigation using the behavioral risk factor surveillance system data for Ohio

This investigation examined potential predictors of obesity and whether an “obesity gap” is present for different demographic groups. The behavioral risk factor surveillance system (BRFSS) data was used for this investigation. This secondary data set provides self-reported and measured biometric information on residents from each state in the United State of America. Results indicated that different income level is not related to body mass index (BMI). However, BMI was significantly different if the individual had a previous diagnosis of diabetes. BMI was also found to be significantly different for different races, as well as the interaction between race and diabetes are associated with BMI.
Simultaneous Living Donor Kidney Transplant and Laparoscopic Native Nephrectomy: An Approach to Kidney Transplant Candidates with Suspected Renal-Cell Carcinoma

Introduction: Kidney transplant candidates are occasionally found during the pre-transplant evaluation to have a suspicious mass in a native kidney. Further work-up and management of such a mass may delay transplantation for several months, which may create logistic barriers to transplant, particularly if there are timing constraints of the donor. In this study, we report our experience with simultaneous living donor kidney transplant and laparoscopic native nephrectomy, where the indication for nephrectomy was a suspicious lesion. Methods: We performed a retrospective review of patients who underwent simultaneous kidney transplant and native nephrectomy using prospectively collected data. We analyzed relevant patient characteristics, surgical details, pathologic results, and long-term follow-up. Results: We identified 16 patients who underwent simultaneous living donor kidney transplantation and laparoscopic native nephrectomy at our institution between 2013 and 2018. Ten (62.5%) patients were found to have renal-cell carcinoma (RCC) on the final pathology. No patients had recurrent RCC, at a median follow-up of 4 years. Conclusion: For patients who are planning to undergo a living donor kidney transplant and are found to have a small mass that is suspicious for RCC, a simultaneous living donor kidney transplant and laparoscopic native nephrectomy is a possible approach in selected patients.
Currency Crisis in the United Kingdom and Hong Kong

This case reviews different varieties of currency crises and two in particular: United Kingdom in 1992 and Hong Kong in 1998. These were two very different types of crises, and understanding them could serve the protagonist well when future crises occurred. Excerpt UVA-GEM-0108 Rev. Feb. 8, 2018 Currency Crises in the United Kingdom and Hong Kong As Arturo Rodrigo was riding the early morning Metro North train from Manhattan to Greenwich, Connecticut, in late December 2010, his thoughts turned to past currency crises. At this point, most emerging markets were struggling to contain the appreciation of their currencies, so perhaps currency crises were not likely in the foreseeable future. But Rodrigo knew conditions could change quickly, so during this quiet holiday season, he would take advantage of the luxury of thinking through issues in relative calm. In another week or so, his days would be too full for proper thinking. Rodrigo set about to refresh his knowledge of currency crises in general, and two specific crises: United Kingdom in 1992 and Hong Kong in 1998. These were two very different types of crises, and understanding them could serve him well when future crises occurred. Fixed Exchange Rates: The Pros and Cons . . .
Patients Are Knowledge Workers in the Clinical Information Space.

Background Limited research exists on patient knowledge/cognition or “getting inside patients' heads.” Because patients possess unique and privileged knowledge, clinicians need this information to make patient-centered and coordinated treatment planning decisions. To achieve patient-centered care, we characterize patient knowledge and contributions to the clinical information space. Methods and Objectives In a theoretical overview, we explore the relevance of patient knowledge to care provision, apply historical perspectives of knowledge acquisition to patient knowledge, propose a representation of patient knowledge types across the continuum of care, and include illustrative vignettes about Mr. Jones. We highlight how the field of human factors (a core competency of health informatics) provides a perspective and methods for eliciting and characterizing patient knowledge. Conclusion Patients play a vital role in the clinical information space by possessing and sharing unique knowledge relevant to the clinical picture. Without a patient's contributions, the clinical picture of the patient is incomplete. A human factors perspective informs patient-centered care and health information technology solutions to support clinical information sharing.
Introduction to the Mini-Series on Lesbian, Gay, Bisexual, Transgender and Questioning Youth: Their Interests and Concerns as Learners in Schools

(2000). Introduction to the Mini-Series on Lesbian, Gay, Bisexual, Transgender and Questioning Youth: Their Interests and Concerns as Learners in Schools. School Psychology Review: Vol. 29, No. 2, pp. 155-157.
The Impact of the COVID-19 Pandemic on the Number of Adolescents/Young Adults Seeking Eating Disorder-Related Care.

Abstract Purpose The COVID-19 pandemic has led to the development and worsening of eating disorder (ED) symptoms in adolescents and young adults. In order to examine COVID-19-related trends in ED care-seeking at our institution. Methods We used interrupted time series regression to examine pre- and postpandemic monthly summary data of the following: (1) ED-related inpatient admissions for medical stabilization; (2) ED-related hospital bed-days; (3) completed outpatient ED assessments; and (4) ED outpatient care-related inquiries at a children’s hospital in Boston, MA. Results Inpatient admissions, hospital bed-days, and outpatient care-related inquiries increased on average over time postpandemic compared to stable volume over time prepandemic (p Conclusion These results indicate increased need for ED-related care during the pandemic. Bolstering resources to meet the needs of these vulnerable patients is critical as the effects of the pandemic continue to be felt.
Permchecker: a toolchain for debugging memory managers with typestate

Dynamic memory managers are a crucial component of almost every modern software system. In addition to implementing efficient allocation and reclamation, memory managers provide the essential abstraction of memory as distinct objects, which underpins the properties of memory safety and type safety. Bugs in memory managers, while not common, are extremely hard to diagnose and fix. One reason is that their implementations often involve tricky pointer calculations, raw memory manipulation, and complex memory state invariants. While these properties are often documented, they are not specified in any precise, machine-checkable form. A second reason is that memory manager bugs can break the client application in bizarre ways that do not immediately implicate the memory manager at all. A third reason is that existing tools for debugging memory errors, such as Memcheck, cannot help because they rely on correct allocation and deallocation information to work. In this paper we present Permchecker, a tool designed specifically to detect and diagnose bugs in memory managers. The key idea in Permchecker is to make the expected structure of the heap explicit by associating typestates with each piece of memory. Typestate captures elements of both type (e.g., page, block, or cell) and state (e.g., allocated, free, or forwarded). Memory manager developers annotate their implementation with information about the expected typestates of memory and how heap operations change those typestates. At runtime, our system tracks the typestates and ensures that each memory access is consistent with the expected typestates. This technique detects errors quickly, before they corrupt the application or the memory manager itself, and it often provides accurate information about the reason for the error. The implementation of Permchecker uses a combination of compile-time annotation and instrumentation, and dynamic binary instrumentation (DBI). Because the overhead of DBI is fairly high, Permchecker is suitable for a testing and debugging setting and not for deployment. It works on a wide variety of existing systems, including explicit malloc/free memory managers and garbage collectors, such as those found in JikesRVM and OpenJDK. Since bugs in these systems are not numerous, we developed a testing methodology in which we automatically inject bugs into the code using bug patterns derived from real bugs. This technique allows us to test Permchecker on hundreds or thousands of buggy variants of the code. We find that Permchecker effectively detects and localizes errors in the vast majority of cases; without it, these bugs result in strange, incorrect behaviors usually long after the actual error occurs.
Children, Computers, and Powerful Ideas.

In the early 1960s, Seymour Papert joined the faculty of MIT and founded the Artificial Intelligence Lab with Marvin Minski. As a mathematician and educational theoretician working in a technology -rich environment, he was in the right place with the right background to consider the educational possibilities of technology. Others had suggested that the computer could serve as a delivery system for presenting content. Papert suggested that the computer could also serve as an environment for “thinking about thinking.”
Retention of perceptual motor skill: an analysis of new methods.

Abstract New methods of determining the amount and type of forgetting pioneered by Bilodeau, Sulzer and Levy were applied to gross perceptual motor skill retention. The changing interdependencies in time of R1, the learned response; KRr, recalled knowledge of results after an interpolated rest interval; and Ra, postrest performance, were studied. No evidence of forgetting occurred except for KRr, which deteriorated in accuracy over a 21 to 23 day rest interval. Limitations of the new paradigm were discussed.
Immunotherapy for Allergic Diseases

Allergic diseases and asthma have increased substantially in prevalence over the last two decades in industrialized countries, and constitute a major public health problem. These diseases are caused by pathological immune responses directed against generally innocuous agents such as environmental respiratory antigens or food antigens, and are characterized by immediate phase responses involving allergen-specific IgE and degranulation of mast cells, resulting in the release of several mediators, including histamine, several proteases as well as cytokines, and arachadonic acid products, including leukotrienes. More importantly, allergic responses are driven and amplified by the development of allergen-specific CD4+ T cells producing high levels of Th2 cytokines (IL-4, IL-5, IL-9 and IL-13), which enhance the growth, differentiation, and recruitment of eosinophils, B cells producing IgE, as well as mast cells and basophils [1]. Together, these cells and factors produce an inflammatory process that is responsible for the symptoms of allergic disease, including urticaria, atopic dermatitis (skin manifestations of allergy), wheezing, airway hyperreactivity or asthma (pulmonary manifestations of allergy), laryngeal edema and hypotension (anaphylaxis), sneezing and nasal congestion or allergic rhinitis (upper respiratory tract), and vomiting and diarrhea or food allergy (gastro-introintestinal manifestations of allergy).
Group dynamics in the state of nature

One common interpretation of the Hobbesian state of nature views itas a social dilemma, a natural extension of the well-knownprisoner's dilemma to a group context. Kavka (1986)challenges this interpretation, suggesting that the appropriate wayto view the state of nature is as a quasi social dilemma. Iargue that Hobbes's remarks on the rationality of keeping covenantsin the state of nature indicate that the quasi social dilemma doesnot accurately represent the state of nature. One possiblesolution, I suggest, views the state of nature as a social dilemmabetween groups rather than individuals. Although thiscleanly represents the strategic problem faced in the state ofnature, it also means we should take intergroup dynamics intoaccount when putting forth a solution. I argue that Hobbes'ssolution of commonwealth by institution – the favored solution forHobbesian social contract theories – will not work in the state ofnature viewed this way.
On Optimal Path and Source Redundancy for Achieving QoS and Maximizing Lifetime of Query-Based Wireless Sensor Networks

Data sensing and retrieval in wireless sensor systems have a widespread application in areas such as security and surveillance monitoring, as well as command and control in battlefield situations. In query-based sensor systems, a user would issue a query with quality of service (QoS) requirements in terms of reliability and timeliness, and expect a response to be returned within the deadline. Satisfying these QoS requirements implies that fault tolerance mechanisms through redundancy will be used, which may cause the energy of the system to be quickly depleted. We develop a hop-by-hop data delivery mechanism in which we utilize "source" and "path" redundancy with the goal to satisfy application QoS requirements while maximizing the lifetime of the sensor system. When given QoS requirements of a query, we identify optimal "source" and "path" redundancy such that not only QoS requirements are satisfied, but also the lifetime of the system is prolonged. Numerical data are presented with physical interpretations given to demonstrate the feasibility of our approach.
Weighted induced L/sup 2/ mixed sensitivity optimization for multi-rate distributed parameter systems

This paper considers the problem of designing near-optimal finite-dimensional controllers for stable multiple-input multiple-output (MIMO) distributed parameter plants under multi-rate sampled-data control. A weighted H/sup /spl infin//-style mixed-sensitivity measure which penalizes the control is used to define the notion of optimality. Controllers are generated by solving a "natural" finite-dimensional sampled-data optimization. A priori computable conditions are given on the approximants such that the resulting finite-dimensional controllers stabilize the multi-rate sampled-data controlled distributed parameter plant and are near-optimal. The proof relies on the fact that the control input is appropriately penalized in the optimization. The technique presented also assumes and exploits the fact that the plant can be approximated uniformly by finite-dimensional systems. Moreover, it is shown how the optimal performance may be estimated to any desired degree of accuracy by solving a single finite-dimensional problem using a suitable finite-dimensional approximant. The constructions given are simple. Finally, it should be noted that no infinite-dimensional spectral factorizations are required. In short, the paper provides a straight forward control design approach for a large class of MIMO distributed parameter systems under multi-rate sampled-data control.
Physician Event Reporting: Training the Next Generation of Physicians

Abstract : Physician reporting of adverse events and unsafe situations remains extremely low, despite the increased access to and use of electronic event reporting systems. We implemented an electronic, Web-based event reporting system at five University of California medical center campuses. While these campuses have witnessed approximately a three-fold increase in staff reporting following the implementation of the electronic system in 2003, physician reporting remains low--only 1.7 percent of all submitted reports were from physicians and only 4.5 percent of registered users are attending physicians and house officers. Our experience validates that of others, specifically, physicians event reporting is a largely elusive practice.
What Are the Harms of Refusing to Allow Living Kidney Donation? An Expanded View of Risks and Benefits

Recent Organ Procurement and Transplantation Network policies relating to living kidney donation (LKD)warrant renewed attention to the ethics of transplantation from living donors. These policies focus on risks related to potential donor evaluation, informed consent and follow-up. The ethical basis of living donation is a favorable risk/benefit ratio for the donor, but regulations and research have given less attention to the benefits of donation. Relatedly, the transplant field has also failed to consider potential harms from denying patients the opportunity to donate. These harms may be substantial in the setting of directed kidney donation to a spouse/partner, sibling or child.We argue that complete assessment of donor risks and benefits demands consideration of not only the risks and benefits of donation, but also those of refusing a donor. In contrast to the ever-expanding literature on risks of donation, there are no data describing outcomes for individuals who were turned down as kidney donors. We consider factors contributing to this omission in the transplant literature, argue that current regulations may perpetuate a narrow understanding of relevant risks and benefits in LKD, and identify areas for improvement in research and clinical practice.
“The Author’s Chair” Revisited

This year marks the 25th anniversary of the publication of Donald Graves and Jane Hansen’s influential article, “The Author’s Chair” (Graves & Hansen, 1983), a report of a study of the relationship...
CHARACTERISTICS OF NEUTRAL CURRENT INTERACTIONS INDUCED BY NEUTRINOS

The ratio of neutral-current to charged-current interactions is measured to be 0.30\ifmmode\pm\else\textpm\fi{}0.03 for isoscalar targets, in good agreement with the results of previous experiments. Two independent methods are employed for isolating neutral-current events, one based on hadronic interactions, and the other on the momentum transverse to the hadron shower. The ratio of neutral-current interactions on neutrons to those on protons is measured to be 1.08\ifmmode\pm\else\textpm\fi{}0.19.
Neurosteroid modulation of recombinant ionotropic glutamate receptors.

Pregnenolone sulfate (PS) is an abundant neurosteroid that can potentiate or inhibit ligand gated ion channel activity and thereby alter neuronal excitability. Whereas PS is known to inhibit kainate and AMPA responses while potentiating NMDA responses, the dependence of modulation on receptor subunit composition remains to be determined. Toward this end, the effect of PS on recombinant kainate (GluR6), AMPA (GluR1 or GluR3), and NMDA (NR1(100)+NR2A) receptors was characterized electrophysiologically with respect to efficacy and potency of modulation. With Xenopus oocytes expressing GluR1, GluR3 or GluR6 receptors, PS reduces the efficacy of kainate without affecting its potency, indicative of a noncompetitive mechanism of action. Conversely, with oocytes expressing NR1(100)+NR2A subunits, PS enhances the efficacy of NMDA without affecting its potency. Whereas the modulatory efficacy, but not the potency, of PS is increased two-fold by co-injection of NR1(100)+NR2A cRNAs as compared with NR1(100) cRNA alone, there is little or no effect of the NR2A subunit on efficacy or potency of pregnanolone (or epipregnanolone) sulfate as an inhibitor of the NMDA response. This suggests that the NR2A subunit controls the efficacy of neurosteroid enhancement, but not inhibition, which is consistent with our previous finding that potentiating and inhibitory steroids act at distinct sites on the NMDA receptor. This represents a first step towards understanding the role of subunit composition in determining neurosteroid modulation of ionotropic glutamate receptor function.
The age-related macular degeneration radiotherapy trial (AMDRT): One year results from a pilot study

Purpose To assess the short-term safety and efficacy of treating subfoveal choroidal neovascularization (CNV) with external beam radiation delivered in 5 × 4 Gy fractions among patients having age-related macular degeneration (AMD). Design A multicenter prospective randomized controlled pilot study. Methods Eighty-eight patients were enrolled through 10 sites and were randomized to radiotherapy (20 Gy delivered in 5 daily fractions of 4 Gy each; 6 MV [N = 41]) or no radiotherapy (sham radiotherapy [N = 22] or observation [N = 25]). Eligibility criteria included visual acuity of at least 20/320 and subfoveal CNV not amenable to treatment. Randomization was stratified by lesion type (new or recurrent CNV) and blood ( Results At baseline, patient and ocular characteristics were similar between treatment groups. At six months, 9 radiated eyes (26%) and 17 eyes not radiated (49%) lost ≥3 lines of visual acuity (P = .04; stratified χ2 test). At 12 months, 13 radiated eyes (42%) and 9 observed eyes (49%) lost ≥3 visual acuity lines (P = .60). The radiated group demonstrated smaller lesions and less fibrosis than the nonradiated group (P = .05 and .004, respectively) at 12 months. Radiation-induced complications were not observed except for one radiated eye with numerous cotton wool spots and possible radiation retinopathy. Conclusions External beam radiation at 5 × 4 Gy may have a modest and short-lived (six month) benefit in preserving visual acuity.
Construction of Tn5 lac, a transposon that fuses lacZ expression to exogenous promoters, and its introduction into Myxococcus xanthus

A promoterless trp-lac fusion fragment was inserted near one end of the bacterial transposon Tn5 in the correct orientation to fuse lacZ gene expression to promoters outside Tn5. The resulting transposon, Tn5 lac, retains the kanamycin-resistance gene of Tn5 and transposes in Escherichia coli at 6% the frequency of Tn5 to many different sites in a bacteriophage lambda target. Expression of beta-galactosidase, the product of the lacZ gene, from Tn5 lac insertions in phage lambda depends both on insertion into a transcription unit in the correct orientation and on the regulation of the promoter of the transcription unit, verifying that by transposition Tn5 lac can fuse lacZ expression to outside promoters. An insertion of Tn5 lac in bacteriophage P1 was isolated and used to introduce Tn5 lac into Myxococcus xanthus, a bacterium that undergoes multicellular development. Stable kanamycin-resistant transductants are obtained that contain no P1 DNA sequences but have Tn5 lac inserted at different sites in the Myxococcus chromosome. Individual transductants express different levels of beta-galactosidase. A chromogenic substrate of beta-galactosidase, 5-bromo-4-chloro-3-indolyl beta-D-galactoside, is toxic in Myxococcus when cleaved in large amounts. In principle, Tn5 lac could be used to assay transcription in any bacterium in which Tn5 can transpose and beta-galactosidase can be measured.