cssi/SciSciGPT-SciSciNet huggingface dataset:
Encrypted communication using chaotic silicon photonic microcavities

We demonstrate encrypted two-party communications using a physically-secure one time pad incorporating two CMOS-compatible chaotic silicon photonic microcavities.
A Bootstrapped PMHT with Feature Measurements

The probabilistic multi-hypothesis tracker (PMHT), a tracking algorithm of considerable theoretical elegance based on the expectation-maximization algorithm, will be considered for the problem of multiple target tracking with multiple sensors in clutter. In addition to position observations, continuous measurements associated with the unique, constant—and statistically unknown —feature of each target are incorporated to jointly estimate the states and features of the targets for the sake of tracking and classification, leading to a bootstrapped implementation of the PMHT. In addition, the information matrix for the stacked vector of states for all the targets at all the time steps during the observation time is derived.
Assesment of distress among breast cancer survivors.

e12610 Background: Several studies have documented distress in breast cancer patients during the diagnosis and treatment phases of cancer care, however, data are more scarce regarding the prevalenc...
Archive of errors: Aḥmad Fāris al-Shidyāq, literature, and the world

ABSTRACTUsing Aḥmad Fāris al-Shidyāq’s semi-autobiographical fictional travel narrative from 1855, this article critiques current world literature paradigms that see literary modernity as the entrance into world literary space’s zones of equivalence. Al-Shidyāq’s text, the article argues, encapsulates debates over the origins of Arabic literary modernity, but rejects both the notion that Arabic literary modernity is a European import and that it is product of a national literary past. Rather, in the author’s reading, al-Sāq represents a combative archive of influences and intertexts that is self-consciously multilinguistic and trans-imperial. Analyzing al-Sāq’s engagement with European texts, the article argues for the power of productive misreadings and corrections, as al-Shidyāq places errors at the centre of his comparative methodology. Reading al-Sāq as participating in and theorizing the nahḍah’s own transnational currents, the article argues that al-Shidyāq analyzes literary and linguistic relations...
Experimental constraints on dynamic fragmentation as a dissipative process during seismic slip.

Various fault damage fabrics, from gouge in the principal slip zone to fragmented and pulverized rocks in the fault damage zone, have been attributed to brittle deformation at high strain rates during earthquake rupture. Past experimental work has shown that there exists a critical threshold in stress–strain rate space through which rock failure transitions from failure along a few discrete fracture planes to intense fragmentation. We present new experimental results on Arkansas Novaculite (AN) and Westerly Granite (WG) in which we quantify fracture surface area produced by dynamic fragmentation under uniaxial compressive loading and examine the controls of pre-existing mineral anisotropy on dissipative processes at the microscale. Tests on AN produced substantially greater new fracture surface area (approx. 6.0 m 2 g −1 ) than those on WG (0.07 m 2 g −1 ). Estimates of the portion of energy dissipated into brittle fracture were significant for WG (approx. 5%), but appeared substantial in AN (10% to as much as 40%). The results have important implications for the partitioning of dissipated energy under extreme loading conditions expected during earthquakes and the scaling of high-speed laboratory rock mechanics experiments to natural fault zones. This article is part of the themed issue ‘Faulting, friction and weakening: from slow to fast motion’.
SINGULAR PERTURBATION APPROACH TO STIFF ESTIMATION

Abstract A singular perturbation scheme is suggested and illustrated for parameter estimation in stiff ordinary differential equations. The approach is sequential in that difficult-to-estimate parameters are introduced in higher order terms of the perturbation solution. This provides excellent initial estimates and avoids the costly repetitive numerical solution of stiff equations. Aspects of data requirement are reviewed for this problem estimation area.
Wisdom and Ruling in the Republic

Few images in Western literature are as vivid as Plato’s cave. In Book VII of the Republic, Plato compares the state of human existence to that of people living in a subterranean cavern. The populace, whose only source of light comes from a fire burning inside the cave, are chained together with their faces permanently turned toward a wall. When objects are passed in front of the fire, the prisoners are only able to view the shadows that these objects cast on the wall, and, in their ignorance, believe that these shadows constitute reality. By chance, a few individuals are torn away from the rest, forced out of the darkness and led upward toward the light. These are the philosophers, who are at first so dazzled by the sight of this higher reality that they are temporarily blinded. When their eyes have become accustomed to the brightness, they recognize that what they had formerly taken for reality is but a poor imitation of it: the fire in the cave pales in comparison to the sunlight, and the objects of which they have seen shadows in the cave were but figurines of the real objects that exist outside. Although they naturally enough desire to remain in their new surroundings, this wish is thwarted when they are forced to return to the darkness and utilize their newfound knowledge to govern the inhabitants below.
Fundamentals of Plasma Process-Induced Charging and Damage

Increasing demands for silicon-based faster microprocessors and denser memories have been historically met by reducing both the thickness of the gate dielectric and the lateral dimensions of logic devices so that many more can be packed on a semiconductor chip [1]. Smaller device dimensions are continuously challenging plasma etching [2], a high-fidelity pattern transfer technique that has become indispensable for semiconductor chip fabrication. Plasma etching has been developed almost exclusively by trial-and-error. The extraordinary complexity of the plasma environment and its interaction with patterned semiconductor surfaces has impeded understanding of the basic physics and chemistry of etching [3]. While significant progress in understanding plasmas, sheaths, and etching reactions has been made through intense and focused research over the past 20 years, no predictive capability exists today to enable a priori design of damage-free etch reactors and processes. Semiconductor manufacturers continue to rely heavily upon the empirical approach to meet the technological challenges of new generations of devices despite the increasing cost and time requirements to solve new problems [2].
The potential of agricultural land management to contribute to lower global surface temperatures

Removal of atmospheric carbon dioxide (CO2) combined with emission reduction is necessary to keep climate warming below the internationally agreed upon 2°C target. Soil organic carbon sequestration through agricultural management has been proposed as a means to lower atmospheric CO2 concentration, but the magnitude needed to meaningfully lower temperature is unknown. We show that sequestration of 0.68 Pg C year-1 for 85 years could lower global temperature by 0.1°C in 2100 when combined with a low emission trajectory [Representative Concentration Pathway (RCP) 2.6]. This value is potentially achievable using existing agricultural management approaches, without decreasing land area for food production. Existing agricultural mitigation approaches could lower global temperature by up to 0.26°C under RCP 2.6 or as much as 25% of remaining warming to 2°C. This declines to 0.14°C under RCP 8.5. Results were sensitive to assumptions regarding the duration of carbon sequestration rates, which is poorly constrained by data. Results provide a framework for the potential role of agricultural soil organic carbon sequestration in climate change mitigation.
The Effect of Interruptions on Novices Learning a Challenging Surgical Skill

The goal of this study was to examine how interruptions affect the acquisition of laparoscopic skills among novices. Undergraduate students with no prior laparoscopic experience completed a basic laparoscopic training task requiring them to pick up and transfer colored objects in a predetermined sequence. The number of colored objects in the sequence was varied to produce three levels of task demand. During execution of the primary task, participants were exposed to a visual interruption by having their video display go blank. The length of interruptions was also varied to examine its effect on memory for the sequence of object moves. Results show greater perceived workload and sequence errors as the demand of the ring transfer task increased. Interruptions from simulated equipment failure were not found to negatively impact recollection of the predetermined color sequences.
GaN PCB Integrated Sensing System for Switch and Capacitor Currents

Gallium nitride (GaN) devices are often installed in a PCB based power electronic system. The parasitic inductance, the lack of galvanic isolation and the large size of existing PCB integrated current sensing techniques degrade the GaN system. Non-invasive giant magnetoresistive (GMR)-based current sensing systems have been integrated in power modules for closed-loop control. The GMRs have also been integrated in load inductors of wide bandgap (WBG) systems for MHz level current sensing. The prior researches haven’t integrated GMRs in the PCBs for currents such as the switch and capacitor currents. To sense these PCB currents without degrading the original system, this paper introduces methodologies for GMR integration in the GaN PCBs. The multi-layer PCBs are divided into several basic structures that can be utilized for sensing. Based on the field properties of the basic structures, optimized detector layout of a multi-GMR sensing system can be decided to achieve accurate current sensing. Switch, DC-link capacitor and AC node currents in a GaN Systems evaluation board are experimentally sensed with the multi-GMR system. The methodologies can be readily applied to a variety of PCB based power converters for current sensing.
Application of elastic parabolic equation solutions to acoustic reverberation in ice-covered underwater environments

Parabolic equation solutions can be obtained for underwater acoustic environments where elastic boundaries affect the acoustic propagation. One example of this situation is in the Arctic where a (potentially rough) ice layer is on top of the water column. The parabolic equation method shown here rigorously applies the zero-traction and fluid-elastic interface boundary conditions to obtain full field Green’s function estimates near the ice-water interface. This solution is crucial for calculation of recently derived reverberation estimates that require both horizontal and vertical derivatives of the complex acoustic field. Monostatic reverberation estimates for a rough under-ice interface are calculated for an upward refracting water sound speed profile and an elastic ocean bottom with a nearly fluid mud layer. These calculations could be used, for example, to estimate areal distribution of the ice layer roughness from azimuth-time dependence of acoustic reverberation measured in Arctic environments. Performance of the Pade rational function approach in the presence of thin ice cover and low shear speed ocean bottom layers will be addressed.
A systematic review of mobile health technologies to support self-management of concurrent diabetes and hypertension.

Objective This article reports results from a systematic literature review of the current state of mobile health (mHealth) technologies that have the potential to support self-management for people with diabetes and hypertension. The review aims to (a) characterize mHealth technologies used or described in the mHealth literature and (b) summarize their effects on self-management for people with diabetes and hypertension from the clinical and technical standpoints. Materials and methods A systematic literature review was conducted following PRISMA guidelines. Online databases were searched in September 2018 to identify eligible studies for review that had been published since 2007, the start of the smartphone era. Data were extracted from included studies based on the PICOS framework. Results Of the 11 studies included for in-depth review, 5 were clinical research examining patient health outcomes and 6 were technology-focused studies examining users' experiences with mHealth technologies under development. The most frequently used mHealth technology features involved self-management support (n = 11) followed by decision support (n = 6) and shared decision-making (n = 6). Most clinical studies reported benefits associated with mHealth interventions. These included reported improvements in objectively measured patient health outcomes (n = 3) and perceptual or behavioral outcomes (n = 4). Discussion Although most studies reported promising results in terms of the effects of mHealth interventions on patient health outcomes and experience, the strength of evidence was limited by the study designs. Conclusion More randomized clinical trials are needed to examine the promise and limitations of mHealth technologies as assistive tools to facilitate the self-management of highly prevalent comorbidity of chronic conditions, such as diabetes and hypertension.
Choice activity stabilizes sensory representations and mediates sensorimotor associations in parietal cortex

Selecting actions which achieve desired goals often requires three-dimensional (3D) representations of the environment. Because the sensory epithelia cannot directly encode the world’s 3D spatial features, sensory signals must be converted into 3D representations. Here we investigated the relationships between the quality of 3D visual representations, choice-related activity, and motor-related activity in the parietal cortex of macaque monkeys using an eight-alternative 3D orientation discrimination task, visually guided saccade task, and laminar probe recordings. We found that choice activity was preferentially carried by caudal intraparietal area neurons with more robust 3D representations. Choice activity further stabilized the 3D representations, rather than attenuating information not directly relevant to the behavioral task (nuisance variables). An experience-dependent, sensorimotor association additionally aligned sensory and saccade direction preferences, particularly for neurons with choice activity. These findings reveal novel roles for choice activity in improving the fidelity of ecologically relevant object representations and mediating sensorimotor associations.
Liberating Hidden Voices: A Feminist Action Research Study to Empower Homeless Women

Within the homeless population in the United States, women are over-represented among homeless families and are under-represented in society and in homeless studies. This feminist action research s...
Sovereign Citizens: A Narrative Review With Implications of Violence Towards Law Enforcement.

Extremist movements are growing in the United States. One concerning extremist group is that of sovereign citizens. Sovereign citizens have been labeled by the Federal Bureau of Investigation as a terrorist threat. Relative to other research about extremist groups, limited research exists about the sovereign citizen movement. The purpose of this article is to review all relevant literature concerning this movement, as it pertains to the threat posed to law enforcement, via descriptive research and to identify existing knowledge gaps. Most empirical work, about sovereign citizens, thus far has focused on legal matters, mental health, radicalization, and postdiction of targeted violence. The work presented here serves as a foundation for future research concerning this group.
Effect of the First Tarsometatarsal (Modified Lapidus) Arthrodesis on Hindfoot Alignment.

The purpose of this study is to demonstrate the effect of first tarsometatarsal (modified Lapidus) arthrodesis on hindfoot alignment. We reviewed the radiographs of 39 patients, 40 feet (16 right feet and 24 left feet in 6 males and 34 females; mean age 43 years) who underwent hallux valgus reconstruction and isolated first tarsometatarsal arthrodesis. Patients who had ancillary osseous procedures were excluded from the study, with the exception of proximal phalangeal osteotomy to address hallux interphalangeus. The mean time to follow up was 33.78 weeks (8.45 months), median 21.5 weeks. Statistically significant differences were found between preoperative and postoperative measurements for talar declination (-3.3 ± 3.5), lateral talocalcaneal angle (-3.1 ± 3.9), lateral Meary's angle (-4.2 ± 4.9), medial cuneiform height (3.5 ± 4.6), medial cuneiform to fifth metatarsal distance (4.7 ± 4.5), AP talocalcaneal angle (-2.8 ± 5.3), and percentage of talar head uncovering (-6.6 ± 7.6). Our results suggest that first tarsometatarsal arthrodesis can affect hindfoot alignment on AP and lateral radiographs.
Systematic examination of protein extraction, proteolytic glycopeptide enrichment and MS/MS fragmentation techniques for site-specific profiling of human milk N-glycoproteins.

Abstract Human milk contains numerous N-glycoproteins with functions that provide protection to the infant. Increasing understanding of the functional role of human milk glycoproteins within the infant requires toolsets to comprehensively profile their site-specific glycosylation patterns. However, optimized methods for site-specific glycosylation analysis across the entire human milk proteome are not available. Therefore, we performed a systematic analysis of techniques for profiling the sites and compositions of N-glycans in human milk using liquid chromatography/mass spectrometry. To decrease interference from non-target molecules, we compared techniques for protein extraction, including ethanol (EtOH) precipitation, trichloroacetic acid precipitation, molecular weight cut-off filtration and techniques for tryptic glycopeptide enrichment, including C18-, porous graphitized carbon and hydrophilic interaction liquid chromatography (HILIC)-solid phase extraction (SPE) and acetone precipitation. We compared the capacity of higher-energy collision dissociation, electron-transfer dissociation and electron-transfer/higher-energy collision dissociation (EThcD) to produce fragment ions that would enable effective identification of the glycan composition, peptide sequence and glycosylation site. Of these methods, a combination of EtOH precipitation, HILIC-SPE and EThcD-fragmentation was the most effective for human milk N-glycopeptide profiling. This optimized approach significantly increased the number of N-glycopeptides and precursor N-glycoproteins (246 N-glycopeptides from 29 glycoproteins) compared with a more common extraction approach with no protein extraction and C18 clean-up (62 N-glycopeptides from 11 glycoproteins). The advancement in methods for human milk N-glycoproteins provided by this study represents a key step for better understanding the function of glycoproteins within the breast milk-fed infant.
Leverage electron properties to predict phonon properties via transfer learning for semiconductors

Electron properties are usually easier to obtain than phonon properties. The ability to leverage electron properties to help predict phonon properties can thus greatly benefit materials by design for applications like thermoelectrics and electronics. Here, we demonstrate the ability of using transfer learning (TL), where knowledge learned from training machine learning models on electronic bandgaps of 1245 semiconductors is transferred to improve the models, trained using only 124 data, for predicting various phonon properties (phonon bandgap, group velocity, and heat capacity). Compared to directly trained models, TL reduces the mean absolute errors of prediction by 65, 14, and 54% respectively, for the three phonon properties. The TL models are further validated using several semiconductors outside of the 1245 database. Results also indicate that TL can leverage not-so-accurate proxy properties, as long as they encode composition-property relation, to improve models for target properties, a notable feature to materials informatics in general.
Antimicrobial susceptibility testing

There continues to be considerable confusion and debate regarding the utility of antimicrobial susceptibility testing (AST) to aid in the antimicrobial selection process. With the renewed emphasis on antimicrobial stewardship in both human and veterinary medicine, it is important to consider all disease preventive and diagnostic tools available. The scientific literature is equivocal regarding the correlation between the in vitro susceptibility test result and clinical outcome. These studies also highlight key points that practitioners should consider when using both individual animal AST results and cumulative diagnostic summaries to select antimicrobial therapeutics.
Some Perspectives on the Transmission of Giardiasis

A number of aspects of the genus Giardia have been a source of great controversy among parasitologists for decades. Much of the difficulty centers around the taxonomy of this flagellate. This has never been completely resolved; it will be discussed further later in this chapter. Giardia spp. investigations proceeded, at a fairly constant level, until the mid-1960s, when research publications pertaining to this parasite diminished considerably. The work with Giardia was continued, over a period of about a decade, by a small group of dedicated workers, without the benefit of much financial support for their research. One reason for this lack of support has been the belief that this organism is of no public health significance in our society. It was considered, and with considerable justification, to be a rather unusual flagellate of doubtful pathologic significance. Many considered it to be more of an exotic parasite, which on occasion produced a diarrheic syndrome in travelers. The research, of course, did progress, and a considerable amount of significant information was developed in such areas as in vitro cultivation (Meyer, 1976; Fortess and Meyer, 1976) and cellular morphology, using both transmission and scanning electron microscopy (Friend, 1966; Erlandsen, 1974; Erlandsen and Chase, 1974; Sheffield and Bjorvatn, 1977) and immunology, by Roberts-Thomson and his co-workers (1976, 1981), Stevens et al. (1978), Visvesvara and Healy (1980), Visvesvara et al. (1980), and many others.
Groebner bases computation in Boolean rings for symbolic model checking

Model checking is an algorithmic approach for automatically verifying whether a hardware or software system functions correctly. Typically, computation is carried over Boolean algebras using binary decision diagrams (BDDs) or satisfiability (SAT) solvers. In this paper we show that computation for model checking can also be carried over the dual Boolean rings of the Boolean algebras by means of efficient polynomial and Groebner basis (GB) computation. We also show how all operations required for model checking can be implemented by means of Groebner bases.
Nuclear proteins. III. The fibrillar nature of the nuclear matrix.

Abstract The nuclear matrix of mouse liver nuclei was examined after extraction of the chromatin with high salt, deoxyribonuclease and Triton X-100. The residual nuclear matrix is composed of a nuclear pore-lamina complex, fibrillar nucleoli, and intranuclear matrix. Whole mount electron microscopy shows that a portion of the nuclear matrix is composed of 20–30 A protein fibers which we call matrixin. The fibers may associate to form larger 100–300 A fibers. When mouse testicular cells were used, intact synaptonemal complexes and the sex vesicle were intimately associated with the matrix and we suggest these structures may be composed of matrixin. SDS gel electrophoresis of the matrix shows three major polypeptides of 65 000, 67 000 and 68 000 D. Several observations suggest DNA is attached to the matrix at many sites throughout the nucleus. The matrix may play a role in the arrangement of chromatin into the chromomeres of meiotic and mitotic chromosomes.
Property based product design using combined property clustering and GC+ techniques

Abstract Property integration techniques have enabled a systematic procedure for the identification of suitable molecules to meet certain process performance. Algorithms exist for identifying molecules with a given set of properties by combining property clustering and group contribution methods (GCM). Yet, there are situations when the property contributions of some of the molecular groups of interest are unavailable in literature. To address this limitation, an algorithm has been developed to include the property contributions predicted by combined GCM and connectivity index (GC + ) method into the cluster space.
The structure of cauliflower mosaic virus. I. A restriction endonuclease map of cauliflower mosaic virus DNA.

A physical map of the genome of cauliflower mosaic virus (CaMV) has been constructed on the basis of the cleavage of CaMV-DNA by restriction endonucleases. Digestion of circular native viral DNA (1) with Eco RI endonuclease produces three fragments, (2) with Hin dIII endonuclease produces nine fragments, and (3) with Bam HI endonuclease produces three fragments from the average virus DNA molecule in the population. The restriction fragments have been ordered by examining the overlapping fragments and the partial digestion products generated by these three restriction endonucleases. Restriction fragments of the virus DNA generated by Eco RI and Bam HI endonucleases have been molecularly cloned in bacterial plasmids in Escherichia coli in order to facilitate restriction mapping of the virus DNA. Evidence for nucleotide sequence heterogeneity in the native virus DNA population is apparent in the form of uncommon restriction endonuclease sites found in only a small portion of the DNA molecules. Examination of molecularly cloned fragments of virus DNA containing these variable sites allowed a more complete analysis of this phenomenon.
Development of the Characteristic Section Method to Estimate Thermal R-Values for Precast Concrete Sandwich Wall Panels

Present methods to estimate the thermal resistance, or R-value, of precast concrete sandwich wall panel include classical calculations methods such as the parallel flow and isothermal plane methods, physical tests, and finite element methods. The parallel flow and isothermal plane methods are shown to provide inaccurate results for sandwich wall panels. Physical tests to determine R-values are expensive to perform. Finite element methods can be cumbersome for routine use in design with currently available software. A new simplified calculation method, called the Characteristic Section M~thod, is proposed to estimate R-values fOyprecast concrete sandwich 'wall panels. The method was developed by studying the heat transfer through the characteristic section in a sandwich panel. The characteristic section is an assemblage of concrete and insulation in a geometrical C~igUration that occurs repeatedly throughout typical sandwich wall panels. (j In the proposed Characteristic Section Method, the panel is divided in to two regions. The first region is treated as a perfectly insulated panel without any thermal bridge. The second region is treated as a solid concrete panel without any insulation. The total thermal resistance .of the panel is calculated as the resistances of these two regions added together in parallel. The portion of the panel that is treated as a solid concrete panel without any insulation is larger than the actual solid concrete regions that exist in the panel. There is an effected
Regulation of Protein Synthesis in Chick Oviduct I. INDEPENDENT REGULATION OF OVALBUMIN, CONALBUMIN, OVOMUCOID, AND LYSOZYME INDUCTION

Egg white protein synthesis is induced and maintained in oviduct magnum of immature female chicks by administering gonadal steroid hormones. The relative rate of synthesis of four egg white proteins (ovalbumin, conalbumin, ovomucoid, and lysozyme) was measured by culturing magnum explants with radioactive amino acids followed by specific immunoprecipitation of each of the egg white proteins. Induction of these proteins was studied as a function of time, hormonal dose, and hormonal combination. A combination of estrogen, progesterone, and testosterone was found which would induce the relative rate of synthesis of each of the four egg white proteins to a level that closely approximates that observed in laying hens; this combination also promotes maximal magnum growth. The synthesis of these proteins is not strictly coordinated, since the rate of synthesis of one or more of these proteins can change relative to the others, although they are all synthesized in the same cell. Noncoordinate protein synthesis is exemplified by the changing ratio of conalbumin to ovalbumin synthesis during both primary and secondary stimulation with estrogen. The ratio of synthesis of these two proteins also changes as a function of the dosage of hormone administered. Furthermore, different combinations of hormones can produce noncoordinate synthesis; for example, the synthesis of ovomucoid and conalbumin is increased relative to ovalbumin when either progesterone or testosterone are administered along with estrogen. The most likely explanation for the change in the ratio of ovalbumin to conalbumin synthesis observed during hormonal stimulation is the 2-fold difference in the rates of degradation of their mRNAs. In contrast, changes in mRNA synthesis or activation best account for the preferential induction of conalbumin synthesis by low doses of estrogen, and the increased rates of conalbumin and ovomucoid synthesis which are produced by supplementing estrogen with either progesterone or testosterone. The results suggest that a single regulatory site for the control of egg white synthesis is unlikely since several of these proteins appear to be under independent control.
Collecting, processing, and storing avian blood: a review

ABSTRACT With recent advances in molecular techniques, collecting blood from birds has become a common practice among field ornithologists. There are a variety of techniques for collecting blood samples and numerous caveats for how samples should be processed, depending on the research question being asked. Currently, few resources are available for individuals learning how to collect blood from birds or needing more information about how to process blood samples. Here, I describe commonly used methods for collecting, processing, and storing blood for particular research objectives, and provide answers to frequently asked questions about blood collection. The information provided is intended primarily for investigators working with passerines, but many techniques and suggestions are applicable to other avian taxa.
Use of translesional coronary flow velocity for interventional decisions in a patient with multiple intermediately severe coronary stenoses

Translesional pressure gradients are currently not performed routinely for most angioplasty procedures because of the technical limitations. With the use of an 0.18 inch Doppler flow velocity guidewire, coronary flow velocity, both proximal and distal to a lesion, can be easily assessed. In branching arteries, significant lesions are characterized by a ratio of proximal to distal flow velocity of > 1.7, loss of the normal phasic diastolic predominant flow velocity pattern, and/or loss of distal hyperemia. We describe the use of coronary flow velocity in assisting important decision making in a young patient with a recent myocardial infarction and multiple coronary lesions. The decision for angioplasty of the hemodynamically significant stenosis was confirmed by translesional flow velocity measurements. A rational approach to coronary intervention in patients with multiple stenoses of intermediate severity appears to be facilitated by direct measurement of translesional flow dynamics. © 1993 Wiley-Liss, Inc.
Synthesis and structural characterization of solvated calcium amides containing bulky silylamide ligands

Abstract A series of solvated calcium bis(amides) with the general formula Ca[N(R)(SiMe3)]2(solv)x (R = –SiMe2t-Bu, –SiPh2t-Bu, and –SiPh3) was prepared from the reaction of CaI2 with 2 equiv of the corresponding potassium amide. Solvent ligands used in this study include THF, pyridine (py), hexamethylphosphoranide (HMPA), and 4-dimethylaminopyridine (DMAP). The coordinated THF in Ca[N(SiMe2t-Bu)(SiMe3)]2(THF)2 could be replaced by stronger donating ligands. When –N[(SiPh3)(SiMe3)] was used as the amide ligand again a bis(THF) adduct was formed. Quite interestingly, when the more sterically-demanding ligand –N[(SiPh2t-Bu)(SiMe3)] ligand was used only one THF molecule could coordinate to Ca, leading to a rare example of a tri-coordinate Ca bis(amide). One of the starting amides, [KN(SiMe2t-Bu)(SiMe3)]2, was isolated and found to adopt a dimeric structure in the solid state. All complexes were characterized with 1H NMR, 13C NMR, elemental analyses, and X-ray crystallography when appropriate.
Determination of the decomposition of aspirin

Bis(truns-2,3-dimethylaziridinyl)phosphinyl urethan (IV) was synthesized and compared with the corresponding cis-2,3- dimethyl derivative (111). The comparative alkylating activities and rates of hydrolysis of these two stereoisomeric aziridine derivatives, 111 and IV, were determined and compared with corresponding data for the monomethyl derivative (V) and two other clinically tested members of this series of antineoplastic agents (dual antagonists), AB-100 (I) and AB-132 (11). The structures of the final hydrolysis products of 111, IV, and V were determined and confirmed by direct synthesis. The results indicate that the mechanisms of hydrolysis of 111, IV, and V (as that of the unsubstituted aziridine derivative, AB-100) are essentially sN2, in contrast to the much faster hy- drolysis of the 2,2-dimethylaziridine analog, AB-132, which in- volves a carbonium-ion mechanism. These studies give further support to the hypothesis that the unique pharmacologic properties of AB-132, as compared to other members of this series, may be related to the unique chemical properties of the 2,2-dimethyl- aziridine moieties. Keyphrases 0 Antineoplastic agents-reaction mechanisms 0 Bis- (trans-2,3-dimethylaziridinyl)phosphinyl urethan-synthesis 0 Alkylating activity-cis-, trans-2,3-dimethylaziridine analogs 0 Hydrolysis mechanism-ring-substituted aziridine derivatives 0 IR spectrophotometry-identity 0 NMR spectroscopy-identity The synthesis of a series of bis( 1-aziridiny1)phosphinyl carbamates, termed “dual antagonists” (I and its analogs containing different carbamate moieties) (1, 2), and their antineoplastic activities in experimental animals (3, 4) and in man (5-9) were previously reported. In an effort to decrease the hematologic toxicity due to the “alkylating” aziridine groups, derivatives were syn- thesized in which the C-atoms of the aziridine rings were substituted with methyl or ethyl groups (10). One member of this new series, ethyl bis(2,Zdimethyl1- aziridiny1)phosphinyl carbamate (AB-132, 11), has been studied to a considerable extent experimentally (1 1) as well as clinically (12-17). Its interesting pharmaco- logic properties [e.g., cholinesterase inhibition (1 8-20)] and its radiation potentiating effect (2 1-23) suggested that this compound may act by a different mechanism than the C-unsubstituted aziridine derivatives (24). This conclusion was supported by chemical studies of its hydrolytic and alkylation reactions (1 1, 25), which in- dicated that the unique properties of I1 may be related to the ability of the 2,2-dimethylaziridine group to participate in S N ~ reactions with its substituted carbon (by forming a tertiary carbonium ion) and, alternatively,
A new fungus parasitic on nematodes.

In the summer of 1931 the writer decided to make a final examination of certain fungi that had developed in a moist chamber in which a batch of strawberry plants had been kept for about three weeks. In the material, his attention was attracted by a fungus with conidia-like bodies having the form of complete, hyaline rings (plate 35, figs. i, g, n). The thickness of the hypha in the rings was considerably greater than that of the simple, septate branches on which they were produced. The content of the rings was also more dense than that of the hyphae even at the early stages of their growth; later on the branches were observed to be practically void of protoplasm. In some mounts rings both attached to the mycelium and detached were observed in considerable numbers. The detached rings were without any remnants of the hyphae (plate 35, fig. n). Thus they were plainly differentiated from the mycelium and ap? peared to answer our usual conception of conidia; they are here considered as such. In most cases the septation was indistinct or absent in the rings (plate 35, fig. n) ; however, infrequently the septation was quite clearly observed (plate 35, fig. i). On further examination of the fungus it was found to produce other differentiated bodies, from globular to oval in shape (plate 35, figs. e and h), on branches similar to the conidiophores terminating with the rings. These resemble young terminal chlamydospores so common in some species of Fusarium. Besides these two no other differentiated bodies were observed; and from the beginning it was suspected that the globular bodies were the first stage in the development of the ring-shaped conidia, even though it was not easy to visualize the process of develop? ment from the first to the second stage. However, in the mate? rial observed this year it was found that the globular bodies at a certain time send out a somewhat pointed tube which, as it 258
Women, Men, and Market Gardens: Gender Relations and Income Generation in Rural Mali

As part of an ongoing process of socioeconomic transformation commodity production is steadily becoming more common throughout rural Africa. However research from a wide range of social and geographic settings indicates that factors such as ethnicity class age and gender often play important roles in shaping specific patterns of participation in market production. This paper explores the relationship between gender and commodity production in central Mali. Drawing on the findings of a 14-month ethnographic study (1992-1994) I describe production dynamics in a rural Bamana farming community paying particular attention to the organization of commercial activities. I use the gender relations of production framework to highlight the differential participation of men and women in commercial gardening activities. I argue that dominant Bamana social and cultural patterns lead to a gender-biased system of access to commercially viable productive resources and I discuss the implications of these findings in terms of mens and womens economic standing and relative social power in their home communities and domestic groups. By providing a detailed study of gender relations in this setting I aim to improve our understanding of the gendered nature of agricultural production in this region and our understanding of differential response to commercial agricultural opportunities in rural Africa at large. (authors)
COLONIZATION OF AGRICULTURAL WINDBREAKS BY FOREST TREES: EFFECTS OF CONNECTIVITY AND REMNANT TREES

Planted agricultural windbreaks may provide habitat for forest tree species and facilitate forest regeneration within the agricultural landscape, if the windbreaks are colonized by forest trees. In order to examine the potential for windbreaks to foster forest regeneration, I surveyed the understories of 51 windbreaks in Monteverde, Costa Rica, for forest tree seedlings. The windbreaks had been planted 5-6 yr earlier. Ninety-one forest tree species (including both primary and secondary forest species) were found in the wind- breaks; however, many of the species occurred in low densities. The mean density of forest tree seedlings in the windbreaks was 2.14 seedlings/M2. Landscape factors appeared to have important effects on tree recruitment patterns. Wind- breaks that were connected to forest had significantly higher densities of forest tree seedlings and greater numbers of forest tree species in their understories than windbreaks that were not connected to forest. In particular, connected windbreaks had higher densities and more species of bird-dispersed trees than nonconnected windbreaks. These differences probably reflect the greater activity of frugivorous birds within connected windbreaks and the re- sulting higher input of forest tree seeds. Windbreaks with remnant forest trees had signif- icantly higher densities of forest tree seedlings of other species and more forest tree species than windbreaks lacking remnant trees. By serving as habitats for forest tree species, windbreaks may contribute to the main- tenance of forest trees within agricultural landscapes and serve as tools for forest restoration in the tropics.
The Critical Few Minutes in Scheduling Time‐Varying Queuing Systems

For nonstationary queuing systems where demand varies over time, an important practical issue is scheduling the number of servers to be available at various times of the day. Widely used scheduling procedures typically involve adding servers at natural time points (e.g., on the hour or at half past the hour) during peak demand periods. Scheduling is often complicated by restrictions on the minimum amount of time (human) servers must work, the earliest (or latest) time a server is available, and limits on the maximum number of servers that can be used at any one time. This paper was motivated by experience with actual queuing systems that embodied such complications. For these systems common scheduling methods that used “natural” starting times for servers resulted in needlessly long customer waits. This research demonstrates that changing the starting times of servers by only a few minutes can have dramatic impacts on customer waiting times for extended periods. In addition, the results highlight the importance of server punctuality.
Narrating Progressivism: Unitarians v. Pluralists v. Students.

History textbooks resemble encyclopedias. They are thick, heavy, and crammed with information divided into subchapters and columns. When students cite the textbook during class discussions, they invariably remark, "the book says . . . ," as if the words had no author. In fact, of course, five or six names appear on the cover, but the plethora implies that all of them wrote every sentence-history by committee. Textbook titles add to this sense of depersonalized information.' I can never remember whether the one I am using this year is American History or America's History or The American People or A People and a Nation. If they differ at all, it would seem to be in style. This one has zestier prose, that one is segmented into shorter subchapters, the next one has more photographs, but beneath the surface, they all apparently contain the same basic array of information arranged into roughly the same sequence of chapters. In the prefaces the authors have candidly explained their frames of reference and interpretations, but after their first pages the textbooks resemble truth books. As a result they reinforce our students' assumption that history is "out there" waiting to be received, like Scripture. Although I long ago discarded that assumption, I found it harder to differentiate the "truths" told by textbooks. Each year when the time came to order for the upcoming survey course, I would follow the most enthusiastic recommendation from one or another fellow teacher or, failing that, reorder the one I was using. This review has helped me define subtler and more reliable criteria. After sitting down with eight textbooks that my colleagues or I have used and comparing their accounts of Progressivism, I recognize that they differ not merely in literary and visual style but also in interpretation and, most significantly, in the overall shape they give to
Rotational raman generation with near-unity conversion efficiency

We demonstrate collinear generation of equidistant rotational sidebands in low-pressure molecular hydrogen with near-unity conversion efficiency. The spectrum consists of 37 coherent sidebands covering over 20,000 cm-1 of spectral bandwidth and ranging from 1.37 µm to 352 nm in wavelength.
Laparoscopic uterine artery occlusion for symptomatic leiomyomas.

Study Objective. To describe a laparoscopic technique that safely occludes both uterine arteries, overcoming an altered surgical field resulting from scarring and/or uterine leiomyomatous growth. Design. Prospective analysis (Canadian Task Force classification II-2). Setting. Nonprofit community hospital. Patients. Eight women with leiomyomas with abnormal uterine bleeding, pelvic pain or pressure, and/or anemia. Intervention. Bilateral laparoscopic retroperitoneal uterine artery occlusion. Measurements and Main Results. Occlusion at the initial track of the uterine artery was performed by laparoscopic coated ligature in six patients. In two obese patients with deep retroperitoneal space, vascular clips were placed endoscopically using the same dissecting technique. All patients were discharged within 20 hours after the procedure. All five women with abnormal bleeding reported satisfactory decrease; none reported amenorrhea. Of eight with preoperative pain or pressure, seven reported complete disappearance and one significant relief. All three patients with anemia had normal red cell counts after 1 month. Conclusion. Laparoscopic uterine artery occlusion using a lateral retroperitoneal technique is safe and effective in women with pelvic scarring and altered pelvic anatomy.
Intramolecular Diels-Alder reactions of 1,3,8-nonatriene and 1,3,9-decatriene

Abstract The stereoselectivities of the title reactions have been investigated from 140–340°C, and relative activation parameters for cis and trans product formation have been determined.
Photodamage of a Mn(III/IV)-oxo mixed-valence compound and photosystem II: evidence that a high-valent manganese species is responsible for UV-induced photodamage of the oxygen-evolving complex in photosystem II.

Abstract The Mn cluster in photosystem II (PS II) is believed to play an important role in the UV photoinhibition of green plants, but the mechanism is still not clear at a molecular level. In this work, the photochemical stability of [Mn III (O) 2 Mn IV (H 2 O) 2 (Terpy) 2 ](NO 3 ) 3 (Terpy = 2,2′:6′,2″-terpyridine), designated as Mn-oxo mixed-valence dimer, a well characterized functional model of the oxygen-evolving complex in PS II, was examined in aqueous solution by exposing the complex to excess light irradiation at six different wavelengths in the range of 250 to 700 nm. The photodamage of the Mn-oxo mixed-valence dimer was confirmed by the decrease of its oxygen-evolution activity measured in the presence of the chemical oxidant oxone. Ultraviolet light irradiation induced a new absorption peak at around 400–440 nm of the Mn-oxo mixed-valence dimer. Visible light did not have the same effect on the Mn-oxo mixed-valence dimer. We speculate that the spectral change may be caused by conversion of the Mn(III)O 2 Mn(IV) dimer into a new structure - Mn(IV)O 2 Mn(IV). In the processes, the appearance of a 514 nm fluorescence peak was observed in the solution and may be linked to the hydration or protonation of Terpy ligand in the Mn-oxo dimer. In comparing the response of the PS II functional model compound and the PS II complex to excess light radiation, our results support the idea that UV photoinhibition is triggered at the Mn 4 Ca center of the oxygen-evolution complex in PS II by forming a modified structure, possibly a Mn(IV) species, and that the reaction of Mn ions is likely the initial step.