cssi/SciSciGPT-SciSciNet huggingface dataset:
SpamHD: Memory-Efficient Text Spam Detection using Brain-Inspired Hyperdimensional Computing

Brain-inspired hyperdimensional Computing (HDC) leverages the mathematical properties of high-dimensional vectors (hypervectors) which show remarkable agreement with how brain functions. Hypervectors (HVs) are high-dimensional (e.g., 10,000 dimensions), holographic, and (pseudo)random with independent and identically distributed (i.i.d) components. Recently, HDC has demonstrated promising capability in a wide range of applications such as robotics, bio-medical signal processing, and genome sequencing. Text spam detection is a classic natural language processing (NLP) task that is usually solved using machine learning methods associated with data preprocessing techniques such as tokenization. In this paper, we develop a memory-efficient text spam detection approach called SpamHD based on HDC methods. In addition to the conventional tokenization-based approach, we also develop a tokenization-free HDC approach with N-gram encoding. Experimental results on three real-world spam datasets (Hotel review, SMS text, and YouTube comments) show that SpamHD is able achieve similar or even outperform baseline tokenization-based learning methods, but with significantly less storage requirements (30X-115X model size reduction). Further, we perform a design space exploration for SpamHD by tuning the number of dimensions of HVs and encoding methods, and evaluate the impact of such design parameters on accuracy and memory requirements.
Hard Cases and Legal Validity: The Internal Moral Significance of Law

One of Hart’s central insights about law, and his major advance over Austin, is to argue for law’s internal normative structure, and to place this at the centre of his theory of law. Hart not only showed that law consists of an ordered system of rules rather than a collection of commands backed by threats, but he also argued that this internal normative framework is essential for a theory of law. This paper argues for the moral significance of law so conceived. As against instrumentalist accounts of law, I argue that it is the internal normative structure of law that gives it its distinctive moral force. Here, I argue that the moral significance of such an internally structured system of rules is lost or distorted when one focuses on law’s external ends. With this understanding of law in mind, I argue, positivists can solve the difficulty of hard cases raised by Riggs v. Palmer, which is often understood to raise a problem of external moral considerations in law. I argue that the internal normative structure that Hart places at the centre of his account of law is sufficient for positivists to meet this challenge raised by Dworkin and his followers.
Using the I-LEARN Model to Design Information Literacy Instruction

An experimental study examined whether information literacy skills instruction designed using the I-LEARN model increased student (N=112) understanding and application of information literacy concepts. While the analysis of the results of pre- and post-test scores and scores on a citation analysis showed that there was no significant difference between the two groups, students in the experimental group used the I-LEARN-designed research guide more often that students in the control group. This warrants further study, and the author is currently working with others to use I-LEARN as a framework to design research guides.
Sources and Composition of Whey and Permeate

Whey, a by-product from cheese or casein manufacture, originates from mammal’s milk, as do its permeates. (The clear yellowish liquid resulting from making soybean curd or soy cheese is sometimes called whey, which should not be confused with whey from mammal milk.) Milks differ depending on origin of specie but all varieties will contain similar gross components but in different amounts.
Transient expression of cyclin D1 is sufficient to promote hepatocyte replication and liver growth in vivo

Cyclin D1 regulates mitogen-dependent progression through G(1) phase in cultured cells, and its overexpression in malignant cells is thought to contribute to autonomous proliferation in vivo. However, previous studies in cell lines have not demonstrated that cyclin D1 is sufficient to trigger cell replication. In this study, we found that transient transfection of adult hepatocytes with cyclin D1 stimulated assembly of active cyclin D1/cdk4 complexes, robust hepatocyte proliferation, and liver growth in the intact animal. After several days, hepatocyte proliferation was inhibited despite the persistence of high levels of cyclin D1 and cyclin E, suggesting that endogenous antiproliferative mechanisms were induced. Our data suggest that this antiproliferative response includes the marked up-regulation of p21, which in turn inhibits cyclin D1/cdk4 and cyclin E/cdk2 complexes. This study offers further evidence that cyclin D1 plays a pivotal role in the regulation of hepatocyte proliferation in the liver. Furthermore, this model may offer a unique system to study the normal cellular response to cyclin D1 expression in vivo.
Genetic Variation of Human Mononuclear Leukocyte Lysosomal Acid Lipase Activity Relationship to Atherosclerosis

Abstract Lysosomal acid lipase activity was measured in mononuclear leukocytes of patients selected on the basis of premature cardiovascular disease, with or without hyperlipidemia. Enzyme activity was significantly lower in the patient population (4.8 ± 1.3 nmol/min/mg protein, n = 190 males) than in an age-matched control population (5.4 ± 1.3 nmol/min/mg protein, n = 124 males. There was no effect of hypercholesterolemia or hypertriglyceridemia on the enzyme activity. In the group of patients with normal plasma lipids (n = 77),18% had mononuclear leukocyte acid lipase activity which fell below the control population 5th percentile, and in the range of enzyme activity observed in cells from obligate heterozygotes for inherited acid lipase deficiency (Wolman disease and cholesteryl ester storage disease). Studies of acid lipase activity in families of our patients provided evidence that an autosomal mutation is associated with (or responsible for) this reduced enzymatic activity and may represent an independent risk factor for the premature development of atherosclerosis.
Discrete mathematics with algorithms

Partial table of contents: SETS AND ALGORITHMS: AN INTRODUCTION. Binary Arithmetic and the Magic Trick Revisited. Algorithms. Set Theory and the Magic Trick. Set Cardinality and Counting. ARITHMETIC. Exponentiation: A First Look. Three Inductive Proofs. How Good Is Fast Exponentiation? The ''Big Oh'' Notation. ARITHMETIC OF SETS. Binomial Coefficients. Permutations. The Binomial Theorem. NUMBER THEORY. Greatest Common Divisors. The Euclidean Algorithm. Fibonacci Numbers. Congruences and Equivalence Relations. An Application: Public Key Encryption Schemes. GRAPH THEORY. Building the LAN. Graphs. Trees and the LAN. Graphical Highlights. Index.
Leadership Matters: Addressing the Student Success and Completion Agenda

This chapter describes a movement to significantly increase student attainment in community and technical colleges. The observations of Leadership Coaches in Achieving the Dream, developed over a nine-year period of involvement, provide insight into the leadership required to transform institutional culture.
The problems with heuristics for law.

A large body of evidence, now familiar to the legal community,demonstrates that individual judgment and choice is often driven by heuristic-based reasoning as opposed to the pure optimization approach presumed by rational choice theory. The evidence of heuristic-based reasoning presents several challenges for consequentialist legal scholars who wish to make normative public policy recommendations. First, the fact that actors subject to the legal system often rely on heuristics suggests that their behavior will not always maximize their subjective expected utility, undermining the traditional assumptions of law-and-economics scholarship that private contracts are necessarily Pareto efficient and that legal taxes and subsidies can cause actors to behave in a way that maximizes social efficiency. Second, the fact that the decision makers who create law also rely on heuristics suggests that law will not necessarily maximize the desired ends of lawmakers, whether those ends are the collective good or the utility of favored groups, and that law that attempts to create incentives for certain behaviors might not be properly calibrated to its goal. Parts I and II of this essay describe these two problems that heuristics cause for law, and Part III considers steps that lawmakers can take to mitigate the problems. This essay was prepared for the June 2004 Dahlem Conference on Heuristics and the Law.
Distributional costs of the housing-price bust

Cynthia Bansak St. Lawrence University Martha A. Starr American University March 2011 Abstract In considering whether asset-price bubbles should be offset through policy, an important issue is who pays the price when the bubble bursts. A bust that reduces the wealth of well-off households only may have small welfare costs, but costs may be sizable if broad swaths of households are affected. This paper uses micro data from the American Community Survey to examine how the recent housing bust affected households‟ employment, homeownership, home values, and housing costs. To separate dynamics of the housing bust from those of the aggregate downturn, we differentiate between metropolitan areas that did and did not experience bubbles. We find that, for most measures, deteriorations in well-being were more severe in bubble metros than elsewhere, and for several measures, differential effects on less-educated households were also more severe. This underscores the importance of keeping housing markets from overheating, as burdens of adjustment fall differentially on people not well prepared to bear them. JEL codes: R21, D31, D12, E32 ____________________________________________________________________ Please address correspondence to: Martha A. Starr, American University, Department of Economics, 4400 Massachusetts Ave. NW, Washington, DC 20016-8029. Phone: 202-885-3747. Email: mstarr@american.edu. We are grateful to Ren Farley, Lisa Neidert, and Al Anderson for their expert guidance in the use of the American Community Survey data, and to session participants at the 2010 ASSA meetings and 2011 EEA meetings for valuable comments on earlier versions of this work.
Approximation of delay systems with applications to control and identification

Abstract : We discuss approximation ideas for functional differential equations and how these ideas can be employed in optimal control and parameter estimation problems. Two specific schemes are described, one based on integral averages of the function being approximated, the other based on best L2 spline approximations. An example illustrating numerical behavior of these schemes applied to an optimal control problem is presented. (Author)
Treatment of genetic disease: current status and prospects for the future.

ur genes encode the complex programs that direct normal development and physiologic homeostasis. Defects in these programs result in maldevelopment and/or dyshomeostasis that we recognize as genetic disease. The cause may be a single mutant gene with a major effect, which so compromises a particular developmental or homeostatic system, that malfunction occurs in all environmental circumstances. The result is a monogenic genetic disease, inherited in classic Mendelian fashion as an autosomal recessive, autosomal dominant, or X-linked trait. Alternatively, the mutant gene may have modest effects, but in combination with other disadaptive genes and environmental factors, may produce a multifactorial genetic disease. I will focus mainly on treatment of monogenic disorders because they are understood better and because many are associated with recognizable biochemical abnormalities that suggest therapeutic approaches and/ or provide a means to monitor the effects of treatment.
Kba.62 and S100 protein expression in cytologic samples of metastatic malignant melanoma

The diagnosis of melanoma can be challenging, especially in metastatic lesions, due to the ability of melanoma cells to morphologically mimic carcinoma, sarcoma and even lymphoma cells. Moreover, melanomas can exhibit negative immunostaining for the melanoma markers HMB-45 and MART-1/Melan-A, often used in the diagnosis of this tumor. KBA.62 is a recently described antibody that reacts with benign and malignant melanocytic proliferations. In this study, we report our experience with KBA.62 and S100 protein immunostaining in the diagnosis of metastatic melanoma on fine-needle aspiration and effusion samples. We reviewed 60 cytology samples from 58 patients with metastatic melanoma. Our results showed that KBA.62 stained 75% of the cases and S100 protein 87% of the cases. KBA.62 and S100 protein stained the majority of metastatic melanomas that were negative for HMB-45 and MART-1; KBA.62 stained 73% of the cases and S100 protein 73% of the cases. The majority (85%) of the cases negative for HMB-45 and MART-1 were positive for KBA.62 and/or S100 protein. Additionally, we also observed that KBA.62 staining was positive in the majority of epithelioid and spindle cell type melanoma cells. In conclusion, the performances of KBA.62 and S100 protein were similar and both markers are useful in the diagnosis of metastatic melanoma in cytology material, especially when the tumor cells lack expression of HMB-45 and MART-1.
100% Complete response rate in patients with cutaneous metastatic melanoma treated with intralesional interleukin (IL)-2, imiquimod, and topical retinoid combination therapy: Results of a case series

Background Patients with cutaneous melanoma metastases have experienced excellent responses to intralesional interleukin (IL)-2. This has led to its recent inclusion into the US National Comprehensive Cancer Network guidelines for management of cutaneous melanoma metastases. Despite this, intralesional IL-2 has not been highlighted in the US literature nor have US physicians adopted it. Objective We sought to evaluate the effectiveness of intralesional IL-2 combined with topical imiquimod and retinoid for treatment of cutaneous metastatic melanoma. Methods A retrospective case series of 11 patients with cutaneous metastatic melanoma were treated with intralesional IL-2 combined with topical imiquimod and retinoid. Results A 100% complete local response rate with long-term follow-up (average of 24 months) was seen in all 11 patients treated with this proposed regimen. Biopsy specimens of treated sites confirmed absence of malignant cells. The most common treatment-related adverse event was rigors. Limitations Small number of patients, retrospective review of charts, and lack of a comparison group were limitations. Conclusion Intralesional IL-2 administered concomitantly with topical imiquimod and a retinoid cream is a promising therapeutic option for managing cutaneous melanoma metastases. The regimen was well tolerated and should be considered as a reasonable alternative to surgical excision.
Health and Lifestyle Issues as Risk Factors for Homelessness

Background: The objective of this study was to test the hypothesis that there are health and lifestyle issues among homeless persons that differentiate them from other segments of the population and that can be described as risk factors for homelessness. Methods: This case-control study investigated health and lifestyle issues in a panel of patients visiting a health care clinic for homeless persons. The same information was collected from a panel of county indigent patients and an equal number of privately insured patients enrolled in a nearby academic family practice center. Results: We found significant differences among these three groups. Differences in health problems were evident, as significantly more homeless persons reported mental health, drug and alcohol abuse, and smoking problems. There were no differences in the prevalence of other general medical conditions as listed by the patients. Homeless persons were younger than the control group respondents and more likely to be male, a member of a minority group, and unmarried. The childhood experiences of homeless persons were distinctive; they were more likely to have lived in a group home or some other nonfamily situation, considered themselves to have been delinquent, run away from home, been expelled from school, or been placed in reform school. The same held true for having been in jail as an adult. They had significantly less education, their job experiences were in manual and unskilled arenas, and they were more likely to have a gambling problem. A continuum of risk also appeared in that for the most part the characteristics and experiences of the indigent group members ranked in frequency between those of the homeless and insurance groups. Conclusions: Causes of homelessness appear to be multifactorial. Issues related to mental health, alcohol, nicotine, and other drug and substance abuse could be responsible for their medical problems, whereas other lifestyle issues might be regarded as risk factors for homelessness.
Association between systemic inflammatory markers and serum prostate-specific antigen in men without prostatic disease - the 2001-2008 National Health and Nutrition Examination Survey.

Background Serum prostate specific antigen (PSA) may be elevated in otherwise healthy men; systemic inflammation has been associated with cancer. The study of systemic inflammatory markers in men without clinical prostate disease, but with elevated PSA may characterize the subgroup of men at higher risk for subsequent prostate cancer. Methods We investigated the associations between systemic inflammatory markers and serum PSA in 3,164 healthy men without prostatic disease, aged >40 years, from the 2001 to 2008 U.S. National Health and Nutrition Examination Survey (NHANES). Serum total PSA levels and concentrations of serum C-reactive protein (CRP) and plasma fibrinogen, neutrophil count, lymphocyte count, and platelet count were recorded. Neutrophil-lymphocyte ratio (NLR) ratio and platelet-lymphocyte (PLR) ratio were calculated. PSA elevation was defined as levels equal or greater than 4 ng/ml. Results Elevated serum PSA (194 men, 6.1% of the total), was significantly associated with plasma fibrinogen (ORmultiv = 1.88; 95% CI, 1.09-3.25), and NLR (ORmultiv = 1.14; 95% CI, 1.03-1.26), after adjustment for age, smoking, body mass index, education, race, co-morbidities, and use of medications. Conclusions Markers of systemic inflammation were associated with elevated PSA in men without known prostatic disease. Future studies are needed to examine these markers' relationship with prostate cancer occurrence and progression.
Urban Goods Movement Planning Methodology

Until the recent past, the urban transportation planning process has not given full consideration to the question of urban goods movements. Local, regional, state, and federal agencies have, however, recently recognized the need for an urban goods movement planning methodology that can be an integral part of the urban transportation planning process and they have expressed support for its integration. A proposed methodology is presented that attempts to draw both short-run and long-run planning considerations into one planning framework. An examination of how the proposed methodology can be integrated into the traditional urban transportation planning process is presented. The implementation of the proposed methodology will enable the planner to make forecasts for future urban goods movements and more effectively plan for facilities to accommodate both goods and people movements.
The Clean Water Act

The Clean Water Act established the priorities and structure for regulating pollution releases into the waters of the United States. The Act's major subchapters include six Titles: (I) Research and Related Programs, (II) Grants for Construction of Treatment Works, (III) Standards and Enforcement, (IV) Permits and Licenses, (V) General Provisions, and (VI) State Water Pollution Control Revolving Funds. The Act continued requirements to set water quality standards for all contaminants in surface waters and made it unlawful to discharge any pollutant from a single, or point, source into navigable waters, unless permitted. It also funded the construction of sewage treatment plants under the construction grants program and recognized the need for planning to address the critical problems posed by diffuse, or nonpoint, sources of pollution. Keywords: clean water act; NPDES; pollution; nonpoint sources; point sources; water quality standards; effluent standards; toxic pollutants; POTW; safe drinking water act
Sediment discharge to the ocean from small mountainous rivers: The New Guinea example

The small mountainous rivers draining the large island of New Guinea (area = 800,000 km2) discharge approximately 1.7 × 109 t of sediment annually, about the same as the combined estimated loads of rivers draining North America. Sediment yields are particularly high for rivers that drain the high mountains of eastern New Guinea, where drainage basins are high and drainage areas small. Owing to the generally narrow (<10 km wide) shelf off eastern New Guinea, much of the fluvial sediment may escape directly to the adjacent deep sea, as evidenced by the presence of sediment-filled trenches. In contrast, many of the rivers draining the south—central part of the island discharge onto a fairly broad shelf, where much of the sediment presumably remains, perhaps as prograding mud wedges.
The Mother Church: Mary Baker Eddy and the Practice of Sentimentalism

“The Mother Church” analyzes the influence of literary sentimentalism on the writings and doctrine of Mary Baker Eddy, the founder of Christian Science. Having attempted a career as a sentimental p...
A 3-dimensional periodic Jacobi-Perron algorithm of period length 8

Abstract The 3-dimensional (cubic) case of the Jacobi-Perron algorithm is considered. In the classes of periodical algorithms hitherto known, the period length was always either 3, or 4, or 9. In Part I, a new class of cubic irrationalities is found whose algorithms are periodical with a period of length 8. In Part II, the algebraic units derived from these algorithms are discussed and found to be equal to the square of a fundamental unit.
Base Camp Personnel Exposure to Particulate Matter During Wildland Fire Suppression Activities

Wildland fire base camps commonly house thousands of support personnel for weeks at a time. The selection of the location of these base camps is largely a strategic decision that incorporates many factors, one of which is the potential impact of biomass smoke from the nearby fire event. Biomass smoke has many documented adverse health effects due, primarily, to high levels of fine particulate matter (PM2.5). Minimizing particulate matter exposure to potentially susceptible individuals working as support personnel in the base camp is vital. In addition to smoke from nearby wildland fires, base camp operations have the potential to generate particulate matter via vehicle emissions, dust, and generator use. We monitored particulate matter at three base camps during the fire season of 2009 in Washington, Oregon, and California. During the sampling events, 1-min time-weighted averages of PM2.5 and particle counts from three size fractions (0.3–0.5 microns, 0.5–1.0 microns, and 1.0–2.5 microns) were measured. R...
Size Matters: Community Size, HIV Stigma, & Gender Differences

Conclusions regarding HIV stigma in rural areas are hampered by lack of agreement about rural classification. This investigation examined perceptions of HIV stigma among males and females with HIV/AIDS in metropolitan, micropolitan, and rural areas. Two-hundred people with HIV/AIDS completed a measure of perceived HIV stigma. Their county or town of residence was used to classify community size. Results indicated that community size was related to one aspect of perceived stigma, disclosure concerns, differently for men and women. Rural women reported more disclosure concerns than did metropolitan and micropolitan women. They also reported more disclosure concerns than rural men. Men in micropolitan communities reported more disclosure concerns than men in rural areas and tended to report more disclosure concerns than men in metropolitan areas. Understanding the relationship of community size to HIV stigmatization requires acknowledging that many communities are neither urban nor rural, and it requires considering gender differences.
Prenatal development of the retina in a diurnal primate (Macaca mulatta).

Observations were made on the pre- and postnatal development of the photoreceptors in the central region of the retina in the diurnal rhesus monkey. Histologic findings on the level of development of the retina at birth revealed a macula with the characteristic adult foveal depression. Observations on the ultrastructural development of the receptor inner and outer segments revealed that the photoreceptors were well differentiated even at birth. An evaluation of the prenatal morphogenesis of the photoreceptors indicated that the initial differentiation may take place as early as 100–125 days after conception. At 100 days after conception, the pigment epithelium consisted of a single layer of cuboidal cells with cytoplasmic content of smooth endoplasmic reticulum, but was only sparsely populated with mitochondria and rough endoplasmic reticulum. The photoreceptor inner segments contained vesiculation in the supranuclear region, while the incipient outer segments consisted of outbudding ciliary processes. By 125 days postconception, the pigment epithelium contained such cytoplasmic specializations as increases in rough endoplasmic reticulum and mitochondria, as well as greater organelle complexity. In the photoreceptor outer segments there were arrays of closed bimembranous discs, with vesiculation at the apical tip in the inner segments. A comparison of the pre- and postnatal ultrastructural changes in the choroid and the interstitial zone comprising the photoreceptor outer segments and the cell processes of the pigment epithelium suggested that the changes in these areas represent a critical aspect in the maturation of the retina.
Left Ventricular Assist Devices Are Underutilized

Heart failure has become one of the fastest growing cardiovascular diagnoses, with estimates as high as 500 000 new cases per year.1,2 This growth is in part a result of the reductions in death from acute coronary syndromes, increased use of implantable cardioverter defibrillators, and improved survival with most cardiovascular interventions, which have led to this continued increase in the number of patients who develop progressive heart failure (HF). The estimated number of people in the United States with the diagnosis of HF may exceed 7 million, based on the estimated average prevalence of 2.6%,3,4 and a census of >300 million population (Figure 1).5,6 HF is clearly age related,1,–,4 with prevalence as low as 0.5% in those 65 years of age.2 This is an important demographic, because it is estimated that the number of people >65 years of age will double in the next 20 to 30 years.4,–,7 HF is not a homogeneous condition. Based primarily on data from recent hospital registries8,9 and other studies,10 nearly half of all patients have HF with preserved systolic function, and the other half have varying degrees of severity of HF with reduced systolic function. Although the prevalence of HF is higher in males at <70 years of age, overall HF is equally common in men and women. Unfortunately, the average survival of patients with either preserved or reduced systolic function is only 40% at 5 years after diagnosis,10,11 and may be as high as 80% when it reaches a refractory stage.12 One study of 3500 patients in Minnesota suggested that there is …
Validation of Ogawa passive samplers for the determination of gaseous ammonia concentrations in agricultural settings

Abstract The Ogawa passive sampler (Ogawa USA, Pompano Beach, Florida) is a useful tool for monitoring atmospheric ammonia (NH3(g)) concentrations and assessing the effects of agricultural waste management practices on NH3(g) emissions. The Ogawa sampler, with filter-discs impregnated with citric acid, was used to trap and determine NH3(g) concentrations in a variety of agricultural settings. A wide range of NH3(g) concentrations can be monitored by varying the sampler exposure time, provided that no more than ∼10 μg of NH3-N are adsorbed on the acid-coated filters. Concentrations less than 1 μg NH3-N m−3 can be detected using long deployments (⩽14 days), while concentrations as great as 10 mg NH3-N m−3 may be determined in very short (e.g. 5 min) deployments. Reproducibility ranged from 5% to 10% over the range of concentrations studied and passive determinations of NH3(g) were similar to those determined using dilute-acid gas scrubbers. Background levels of NH3(g) at a non-agricultural site in southern Delaware were typically
Dp71 can restore the dystrophin-associated glycoprotein complex in muscle but fails to prevent dystrophy

Two lines of transgenic mdx mice have been generated that express a 71 kD non-muscle isoform of dystrophin (Dp71) in skeletal muscle. This isoform contains the cysteine-rich and C-terminal domains of dystrophin, but lacks the N-terminal actin-binding and central spectrin-like repeat domains. Dp71 was associated with the sarcolemma membrane, where it restored normal expression and localization of all members of the dystrophin-associated glycoprotein complex. However, the skeletal muscle pathology of the transgenic mdx mice remained severe. These results indicate that the dystrophin C terminus cannot function independently to prevent dystrophic symptoms and confirms predictions based on patient data that both the N and C-terminal domains are required for normal dystrophin function.
SU‐EE‐A4‐01: CT Number Accuracy of Lung Nodules: Effect of Patient Body Size and Lung Size

Purpose: To investigate the effects of patient body size and lung size on the CT numbers of lung nodules measured with multi‐detector CTscanners and whether improved accuracy can be obtained with a dual‐energy technique. Method and Materials: Simulated lung nodules consisting of 9.5‐mm diameter spheres containing 50mg/cc and 100mg/cc CaCO3 in a water‐equivalent resin were scanned in two simulated thorax section phantoms with a GE VCT scanner. One phantom (A) represented the middle of the chest. It had large simulated lung regions and simulated ribs, heart and spine. The other (B) represented the upper chest. It had a much wider aspect ratio, smaller simulated lung regions, and simulated ribs, scapula, heart, and spine. Fat rings were added to the phantoms to simulate larger patients. Images were acquired on a GE VCT scanner with high‐resolution techniques (0.53:1 pitch, 0.625‐mm slice thickness and interval) at 80, 120 and 140kVp. Scans were repeated 3 times for reproducibility and analyzed using an automated technique. Results: Body size had a significant effect on the measured mean CT‐numbers of the nodules. For phantom‐A, adding fat rings decreased the overall average CT‐numbers of the 50mg/cc nodules at 120kVp by 15HU and those of the 100mg/cc nodules by 21HU. Corresponding reductions in phantom‐B were 9HU and 13HU. The dual‐energy approach (CT#80kVp‐CT#140kVp) reduces the variability, with a maximum difference of 4HU for all conditions. Lung size had a minimal effect with a maximum difference (nodule CT# phantom A ‐ nodule CT# phantom B) of 4.5 HU. Conclusion: Even with modern multi‐detector CTscanners, beam hardening and x‐ray scatter errors due to body size can result in underestimates of the true CT numbers of lung nodules. A dual‐energy approach compensates for these errors and should be considered especially if it can be implemented using a rapid kVp switching technique.
Subclustering of human immunoglobulin kappa light chain variable region genes

The human immunoglobulin kappa light chain (IgK) locus includes multiple variable region gene segments (V[sub k]) that can be divided into four subgroups. Oligonucleotide primers were designed to amplify specifically gene segments of the V[sub k]I, V[sub k]II, and V[sub k]III subgroups using the polymerase chain reaction (PCR). Product sequences were subcloned, sequenced, and compared. Phylogenetic analyses of sequences within each subgroup indicate that some subgroups can be subdivided further into [open quotes]sub-subgroups.[close quotes] The history of V[sub k] segment duplications apparently includes at least two separate periods, the first giving rise to the subgroups and the second generating further complexity within each subgroup. Duplications of large pieces of DNA (demonstrated by others through pulsed-field gel electrophoresis) also played a role. Rates of synonymous and nonsynonymous base changes between pairs of sequences suggest that natural selection has played a major role in the evolution of the V[sub k] variable gene segments, leading to sequence conservation in some regions and to increased diversity in others. 34 refs., 4 figs., 3 tabs.
Class-Selective Detection System for Liquid Chromatography Based on the Streptavidin-Biotin Interaction

A protein binding assay (BA) was coupled with high-performance liquid chromagraphy (HPLC) to provide a highly sensitive postcolumn reaction detection system for the biologically important molecule biotin and its derivatives biocyhn, biotin ethylenediamine, 6-(biotinoylamino)caproic acid, and 6-(biotinoylamino)caproic acid hydrazide. This detection system is selective for the biotin moiety and responds only to the class of compounds that contain biotin in their molecules. In this assay, a conjugate of streptavidin with fluorescein isothiocyanate (streptavidin-FITC) was employed. Upon binding of the analyte (biotin or biotin derivative) to streptavidin-FITC, an enhancement in fluorescence intensity results. This enhancement in fluorescence intensity can be directly related to the concentration of the analyte and thus serves as the analitycal signal. The HPLC-BA system is more sensitive and selective than either the BA or HPLC alone. With the described system, the detection limits for biotin and biocytin were found to be 97 and 149 pg, respectively. Finally, the analysis of an infant formula and several cell culture media, with little or no sample preparation, demonstrated the analytical utility of this system
Comment on "Attenuative Dispersion of P Waves in and near the New Madrid Seismic Zone" by L. Cong, J. Mejia, and B. J. Mitchell

Manuscript received 15 February 2001. Cong et al. (2000) used P -wave dispersion from small earthquakes in the New Madrid Seismic Zone to estimate Q P through the use of a continuous-relaxation model. This technique was used as an alternative to the usual spectral-slope techniques and employed an innovative step of comparing group delays relative to those at a reference frequency in order to reduce the bias in the dispersion due to errors in the assumed distance and velocity. The resultant Q m values showed an increasing trend with distance, which they interpreted as due to an increase of crustal Q with depth and the portion of the wave propagation through an active seismic zone. The method used by Cong et al. (2000) suffers, however, from two important problems. First, their equation for estimating the relative group delay requires a correction that changes their derived relaxation parameters. Second, their use of short signal-duration windows, just the first cycle of the P -wave arrival, to define signal dispersion at periods much greater than the window duration is wrong. These problems lead to several difficulties in the interpretation of their results. A number of causal Q models have been presented in the literature (Ben-Menahem and Singh, 1981). The continuous-relaxation model is constructed as a superposition of relaxation mechanisms such that Q is constant over a passband. For reference, this operator is (Ben-Menahem and Singh, 1981, equations 10.285 and 10.287) \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[\ Q^{-1}(f)=\frac{2}{{\pi}}Q\_{m}^{-1}\mathrm{tan}^{-1}\left[\frac{{\omega}({\tau}\_{1}-{\tau}\_{2})}{1+{\omega}^{2}{\tau}\_{1}{\tau}_{2}}\right],\] \end{document}1 where ω is the angular frequency, τ 1 and τ 2 are the relaxation times, and Q m is approximately Q(f) at intermediate frequencies. An example of this function is plotted in Figure 1. The causal frequency-dependent phase velocity C ( ω ) is given by \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[\ \frac{C({\omega})}{C\_{{\infty}}}=\left\{1+\frac{1}{{\pi}Q\_{m}}\left[\mathrm{ln}\frac{{\tau}\_{1}}{{\tau}\_{2}}+\frac{1}{2}\mathrm{ln}\left(\frac{1+{\omega}^{2}{\ }{\tau}\_{2}^{2}}{1+{\omega}^{2}{\ }{\tau}\_{1}^{2}}\right)\right]\right\}^{-1}\] \end{document}2 Figure 1. Comparison of the Q -1( f ) obtained using the published and corrected dispersion relation. The …
A novel cotton ovule culture: induction, growth, and characterization of submerged cotton fibers (Gossypium hirsutum L.).

The growth of submerged cotton (Gossypium hirsutum L.) fibers from cultured ovules has been investigated. The results indicate that exogenous plant hormone levels regulate the induction of submerged fiber growth. The age of ovules at induction is also important. Cell diameter, wall thickness, and cell length of submerged fibers were measured and compared with air-grown fibers and fibers grown in vivo (produced by cotton plants grown in the greenhouse). Various cellwall thickening patterns were observed among submerged fibers, while only one predominant cell-wall deposition pattern was produced in air-grown fibers and in fibers produced in vivo. The diameter of submerged fibers was about the same as that of air-grown fibers but about 22% less than that of fibers grown, in vivo. It appears that the secondary cell wall thickenings are initiated earlier in submerged fibers. The cell-wall thickness of submerged fibers, at 41 d post anthesis (DPA), was 51% greater than that of fibers grown in vivo, whereas the cell-wall thickness of air-grown fibers was 42% less than that of fibers produced in vivo. The cell length of submerged fibers was approximately half that of fibers grown in vivo. and the air-grown fiber length was about two-thirds of fibers grown in vivo. The age of ovules at induction affects the outcome of the air-grown fiber-cell length, but does not appear to affect the length of submerged fiber cells. To produce submerged fiber growth, we found that the optimal age of ovules at induction was 0 DPA, and the optimal medium (with a GA3 of 0.5 μM and an IAA range of 5-20 μM) depends on the time of ovule induction (−2 to+2DPA). We conclude that conditions leading to submerged cotton fiber growth have great potential for (a) direct monitoring of growth and making precise, detailed measurements during fiber growth and development; (b) producing cellulose and fibers in vitro more efficiently than earlier ovule-culture methods; and (c) using these unique cultures to obtain a better understanding of signal transduction and gene expression leading to growth, development, and programmed cell death in the life history of the cotton fiber.
Conditions for thermal circulation in urban street canyons

Abstract Under conditions of low background winds and high solar radiation, non-uniform heating of building walls and the ground in an urban street canyon may induce thermally driven circulation that competes with inertially driven circulation due to overlying winds. These two types of circulation were studied using a field experiment, wherein a mock building canyon constructed with two rows of north–south aligned shipping containers were subjected to natural differential wall heating and overlying winds of varying magnitude. The site was carefully instrumented, and the measurements and flow visualization were conducted over nine days with varying environmental conditions. A buoyancy parameter, B = ( g α Δ T H ) / ( u 0 2 [ 1 + ( H / L ) 2 ] ) , where gαΔT is the horizontal anomaly of buoyancy arising from differential heating of canyon walls, H the canyon height, L the canyon width and u0 the background velocity, was derived to demarcate thermal and inertial circulation regimes. When B Bc, the thermal circulation becomes important and at B ≫ Bc, the flow is expected to be independent of u0. An intermediate regime is found in the proximity of Bc, where the scaled velocity is dependent both on overlying flow and buoyancy effects.
Analytic Properties of the Teukolsky Equation

The analytic properties of the solutions to the Teukolsky equation in the complex frequency plane are investigated. The scattering coefficientZ in is found to be an analytic function of the frequency except at singularities and at certain branch points in both the upper and lower frequency plane. The implications for the proof of the stability of the Kerr geometry given by Press and Teukolsky are discussed.
Intersections of Sets Starshaped Via Paths of Bounded Length

Let S be a nonempty closed, simply connected set in the plane. For α > 0, let ℳ denote the family of all maximal subsets of S which are starshaped via paths of length at most α. Then ⋂{M : M in ℳ} is either starshaped via α-paths or empty. The result fails without the simple connectedness condition. However, even with a simple connectedness requirement, there is no Helly theorem for intersections of sets which are starshaped via α-paths.
Numerical flow field visualization

The application of computer-generated imagery to analyze numerical solutions of fluid flow is presented. High-performance graphics workstations, their current capabilities, and their use in flow field analysis are discussed. Interactive flow field computations about complex three-dimensional bodies applying computer-generated imagery are projected for the future.
Remote sensing of ocean color: Assessment of the water-leaving radiance bidirectional effects on the atmospheric diffuse transmittance for SeaWiFS and MODIS intercomparisons

Abstract The portion of the radiance exiting the ocean and transmitted to the top of the atmosphere (TOA) in a particular direction depends on the angular distribution of the exiting radiance, not just the radiance exiting in the direction of interest. The diffuse transmittance t relates the water component of the TOA radiance to that exiting the water in the same direction. As such t is a property of the ocean–atmosphere system and not just the atmosphere. Its computation requires not only the properties of the atmosphere but the angular distribution of the exiting radiance as well. The latter is not known until a determination of the water properties can be made (which is the point of measuring the radiance in the first place). Because of this, it has been customary to assume an angular distribution (uniform upward radiance beneath the water surface) in the computation of t, which is referred to as t⁎. However, it is known that replacing t with t⁎ can result in an error of several percent in the retrieved water-leaving radiance. Since the error depends on sun-viewing direction, this error could be particularly important when water-leaving radiance from two or more sensors in different orbits are compared. Even given an estimate of the angular distribution of the water-leaving radiance, computation of t using full radiative transfer theory in an image processing environment is not practical. Thus, we developed a first-order correction to t for bidirectional effects in the water-leaving radiance that captures much of the variability of t with viewing direction. The correction computed across a SeaWiFS scan line shows that a t⁎-induced error of as much as 5–6% could occur near the edges of the scan; however, limiting the scan to polar viewing angles (θ)
Hydrographic conditions of the Devono–Carboniferous North American Seaway inferred from sedimentary Mo–TOC relationships

Abstract Deepwater anoxia developed widely within a series of silled intracratonic basins in North America during the Middle Devonian to Early Carboniferous, but the hydrographic factors contributing to this development are virtually unknown. The present study demonstrates that the degree of enrichment of strongly hydrogenous elements such as molybdenum (Mo) in the organic-rich shales that accumulated in these basins has the potential to provide information about paleohydrographic conditions. Most of the study units (49 of 55) exhibit significant positive covariation between elemental Mo and TOC concentrations, yet there is substantial variation in the statistical parameters that define these relationships. Specifically, the regression lines characterizing Mo–TOC covariation have slopes (m) ranging from ∼2 to 65 (× 10− 4), although a majority of the study units yield m values between 10 and 25 (× 10− 4). The parameter m exhibits systematic stratigraphic variation within individual basins and geographic variation among basins, suggesting that Mo–TOC relationships were controlled by slowly evolving watermass characteristics of the Devono–Carboniferous North American Seaway. A recent study of modern anoxic silled basins [Algeo, T.J., Lyons, T.W., 2006. Mo-total organic carbon covariation in modern anoxic marine environments: Implications for analysis of paleoredox and paleohydrographic conditions. Paleoceanography 21, PA1016. doi:10.1029/2004PA001112] demonstrated that m is closely linked to the degree of restriction of the subpycnoclinal watermass, as reflected in aqueous Mo concentrations ([Mo]aq) and deepwater renewal times (τdw). These relationships reflect control of sedimentary Mo enrichment by both the amount of sedimentary organic matter (i.e., host-phase availability) and the concentration of aqueous Mo (i.e., source-ion availability). When applied to black shales of the Devono–Carboniferous North American Seaway, these relationships permit both qualitative and quantitative inferences regarding the degree of restriction of deepwaters in cratonic basins and the evolution of hydrographic conditions through time. Black shales associated with early stages of sea-level rise commonly exhibit low m values ( 1000 yr. Higher sea-level stands resulted in more open-marine conditions and enhanced deepwater renewal, leading to deposition of black shales with m values up to ∼ 65, equivalent to [Mo]aq > 70% of the normal seawater concentration and τdw
A NUMERICAL SOLUTION TO THE FOKKER-PLANCK EQUATION DESCRIBING THE EVOLUTION OF THE INTERSTITIAL LOOP MICROSTRUCTURE DURING IRRADIATION

Abstract A new calculational method has been developed for the numerical solution of the Fokker-Planck equation describing voids and interstitial loops. Small-size interstitial clusters were studied using a detailed rate theory approach, while largesize loops were simulated by descretizing a transformed Fokker-Planck equation. Interstitial loops containing up to millions of atoms were investigated using this hybrid technique. The numerical results of the model compare reasonably well with previous detailed rate theory calculations, as well as with experimental findings on heavy ion irradiated 316 stainless steel.
Mineral relationships in the ores of Pachuca and Real del Monte, Hidalgo, Mexico

Representative collections of the richer silver ores from the famous Mexican districts of Pachuca and Real del Monte are now available mainly from Museum sources. Microscopic study of excellent collections from the U. S. National Museum reveals an unusual degree of uniformity in the character of the mineralization throughout the area. The primary mineralization represented a single episode characterized by a comparatively simple mineralogy. Pyrite, quartz, and sphalerite were the early hypogene minerals followed by hypogene galena, chalcopyrite, argentite and rarely polybasite and stephanite. The principal primary (hypogene) source of silver is unquestionably argentite. Native silver appears always to be secondary (supergene). Some argentite is also supergene.