cssi/SciSciGPT-SciSciNet huggingface dataset:
Preoperative Therapy for Gastric Adenocarcinoma is Protective for Poor Oncologic Outcomes in Patients with Complications After Gastrectomy

Postoperative complications (POC) are associated with poor oncologic outcomes in gastric cancer. We sought to evaluate the impact of POC on survival in patients with gastric cancer treated with upfront surgery (UpSurg) versus those treated with preoperative therapy (PreT). We analyzed data from a prospectively maintained database of patients who had undergone resection of their gastric cancer at our institution. Patients with T1N0 or M1 lesions, recurrent disease, and mortality within 90 days were excluded. Survival was compared between patients with and without POC in the UpSurg and PreT groups. Cox regression analyses were used to examine factors associated with overall survival (OS) and disease-free survival (DFS). A total of 421 patients underwent resection of gastric cancer: 30% underwent upfront surgery, and 51% had a POC. Among patients who had POCs, 71% were infectious and 53% were Clavien–Dindo grade III or IV. UpSurg patients with a POC had shorter OS (5-year, 47 vs. 85%; p < 0.001) and DFS (5-year, 46 vs. 76%; p < 0.001) than those without a POC. In contrast, there was no difference in OS (5-year, 57 vs. 63%; p = 0.77) and DFS (5-year, 52 vs. 52%; p = 0.52) between PreT patients with and without POC. Multivariable Cox regression model demonstrated that a POC in UpSurg patients had significant impact on DFS (2.6 [95% confidence interval (CI) 1.48–4.74]), whereas it did not in PreT patients (0.9 [95% CI 0.70–1.33]). The use of preoperative therapy negated the impact of POCs on OS and DFS in patients undergoing resection for gastric cancer.
A parallel algorithm for statistical belief refinement and its use in causal reasoning

This paper presents a new approach to efficient parallel computation of statistical inferences. This approach involves two heuristics, highest impact first and highest impact remaining, which control the speed of convergence and error estimation for an algorithm that iteratively refines degrees of belief. When applied to causal reasoning, this algorithm provides a performance solution to the qualification problem. This algorithm has been implemented and tested by a program called HITEST, which runs on parallel hardware.
Policy Implications of

After the speculative attacks on government-controlled exchange rates in Europe and in Mexico, economists began to develop models of currency crises with multiple solutions. In these models, a currency crisis occurs when the economy suddenly jumps from one solution to another. This paper examines one of the new models, finding that raising the cost of devaluation may make a crisis more likely. Consequently, slow convergence to a monetary union, which increases the cost to the government of reneging on an exchange rate peg, may be counterproductive. This conclusion is exactly the opposite of that obtained from earlier models.
Induction of a Spindle-Assembly-Competent M Phase in Xenopus Egg Extracts.

Summary Normal mitotic spindle assembly is a prerequisite for faithful chromosome segregation and unperturbed cell-cycle progression. Precise functioning of the spindle machinery relies on conserved architectural features, such as focused poles, chromosome alignment at the metaphase plate, and proper spindle length. These morphological requirements can be achieved only within a compositionally distinct cytoplasm that results from cell-cycle-dependent regulation of specific protein levels and specific post-translational modifications. Here, we used cell-free extracts derived from Xenopus laevis eggs to recapitulate different phases of the cell cycle in vitro and to determine which components are required to render interphase cytoplasm spindle-assembly competent in the absence of protein translation. We found that addition of a nondegradable form of the master cell-cycle regulator cyclin B1 can indeed induce some biochemical and phenomenological characteristics of mitosis, but cyclin B1 alone is insufficient and actually deleterious at high levels for normal spindle assembly. In contrast, addition of a phosphomimetic form of the Greatwall-kinase effector Arpp19 with a specific concentration of nondegradable cyclin B1 rescued spindle bipolarity but resulted in larger-than-normal bipolar spindles with a misalignment of chromosomes. Both were corrected by the addition of exogenous Xkid (Xenopus homolog of human Kid/KIF22), indicating a role for this chromokinesin in regulating spindle length. These observations suggest that, of the many components degraded at mitotic exit and then replenished during the subsequent interphase, only a few are required to induce a cell-cycle transition that produces a spindle-assembly-competent cytoplasm.
Pressing Issues Among Trainees and Early Career Physicians in Headache Medicine: Survey Results From the American Headache Society New Investigator and Trainee Section and International Headache Academy.

Objective We surveyed the American Headache Society (AHS) New Investigators and Trainees Section (NITS), and International Headache Academy (IHA) attendees to better understand what they perceive as the most pressing issues for themselves as new investigators and trainees in the field of headache medicine. Background The NITS and IHA are intended as platforms for mentorship, leadership training, and professional development in the field of headache medicine. Identifying and addressing pressing issues among new investigators and trainees based on their perceived needs is critical to encouraging their development and success as headache medicine clinicians and researchers. Methods Paper surveys were administered at the NITS meeting at the November 2018 Scottsdale Headache Symposium and the January 2019 IHA. Additionally an online version was sent to the NIT listserv in November of 2018. The survey queried demographic information (gender, race, age, profession, training status, and years in practice) and asked participants to identify their top 3 most pressing issues/questions among a list of options. Results Fifty-three responses were submitted (53/255; total response rate 20.7%). Among the surveys, 18 in-person responses were from the NITS meeting (18/20; response rate 90.0%), 23 in-person responses were from the IHA (23/45; response rate 51.1%), and 12 responses were from the online survey (12/190; response rate 6.3%). No duplicate responses were submitted based on comparison of demographics. One respondent identified as a researcher exclusively and was excluded from further analyses; the rest identified as clinicians at various levels of medical training. Fifteen respondents were not members of the NITS (28.8%); the most common reason for nonmembership was lack of awareness of the section (92.8%). Overall the most pressing issues/questions included (% of respondents who ranked issue/question among top 3): Career planning (51.9%), Logistics of running a headache clinic (40.4%), and Opportunities for involvement (38.5%). Most pressing issues/questions differed depending on level of training. Working with industry was the most pressing issue/question identified by early career physicians (55.0%). Career planning was the most pressing issue/question among fellows (72.2%) and residents (64.3%). Conclusion Many of the most pressing issues identified by respondents are topics that are not formally addressed in medical and research training.
The performance of a new linear light path flow cell is compared with a liquid core waveguide and the linear cell is used for spectrophotometric determination of nitrite in sea water at nanomolar concentrations.

Abstract The sensitivity of a spectrophotometric assay is enhanced either by increasing the concentration of the target molecules within the flow cell or by extending the length of the light path of the flow cell. Determination of nutrients at nanomolar concentrations in sea water has therefore been based either on the preconcentration of the analyte on a microcolumn from a large volume of sample followed by its elution into a conventional 1–2 cm flow cell, or by the use of Liquid Core Waveguide (LCW) with a light path as long as several meters. In order to evaluate the relative improvements of these different approaches to increasing sensitivity we have developed a preconcentration technique for the determination of nitrite in seawater using the Gries reaction and compare its sensitivity and precision to that of non preconcentration techniques using both LCW and Linear Light Path (LLP) cells of different lengths. In this work the performance of the LLP is investigated and compared with the performance of the coiled LCW flow cell. Next, the determination of nitrite, automated by programmable Flow Injection (pFI), was carried out by using LCW and LLP flow cells, as well as by using a 10 cm LLP flow cell together with the preconcentration step of nitrite on a microcolumn. The assay of nitrite in sub micromolar range was most efficiently performed by a combination of pFI with the LLP flow cell without the need for a preconcentration step. The determination was performed at a rate of 40 samples/hour with a Limit of Detection (LOD) = 0.6 nM N using a 50 cm long, and a LOD = 2.5 nM N using a 10 cm long, LLP flow cell. Analysis of sea water samples confirmed that salinity does not affect the sensitivity of the determination. At a much lower cost than LCW, the LLP flow cell can also be easily assembled from components usually at hand in a laboratory.
Severe right-sided heart failure and pulmonary hypertension with carfilzomib treatment in multiple myeloma

Carfilzomib, a second-generation irreversible proteasome inhibitor, is currently considered the preferred therapy for relapsed and refractory multiple myeloma. There are several cardiovascular adverse effects described with carfilzomib chemotherapy most commonly being hypertension, dyspnea and decreased cardiac ejection fraction. We report a case of newonset pulmonary hypertension with right ventricular (RV) heart failure in a patient receiving carfilzomib. Awareness of this rare side effect of this drug is essential for prompt diagnosis and management. We also propose close monitoring of RV and pulmonary artery pressures along with left ventricular function in echocardiographic assessment in patients with carfilzomib chemotherapy.
Long-term initiation time for stress -corrosion cracking of alloy 600 with implications in stainless steel: Review and analysis for nuclear application

Abstract This paper provides a summary and analysis on the initiation of stress -corrosion cracking (SCC) of Alloy 600 (and related alloys) and stainless steels in nuclear reactor environments near 300 °C. Two processes seem to be comparable between traditional slip dissolution/oxidation mechanisms and aging-related crystalline ordering. This paper evaluates various supporting topics, including SCC initiation time, activation energy, stress/strain rate/plastic deformation, electrode potential drop, rate-limiting step, long-term threshold values, and data uncertainties. The understanding of Alloy 600 SCC is extended to stainless steels. SCC mechanisms of nickel-based alloys and stainless steels at lower temperatures are different from nickel-based alloys at higher temperatures. Finally, this paper describes how this work would be potentially considered in the nuclear industry.
“A Very Natural Dream”; or, The Castle of Otranto

This chapter, focused on Walpole’s The Castle of Otranto, demonstrates the ways in which Walpole develops the embryological metaphors of his early poetry into his most famous work of fiction, which not only created a new genre, but also laid the foundation for its most famous immediate successors, the subjects of the remaining chapters. Walpole’s work establishes the philosophical foundations of the Gothic and its focus on the search for origins, a search mediated by the struggle between internal and external sources of identity, the organic and the mechanical, and the natural and supernatural. The prefaces set up the conflict between preformation and epigenesis, which is manifested in the novel in the plot’s focus on family fertility, the biological foundations of the love stories, and in the statue of Alfonso, which becomes a metaphor for epigenetic formation.
Developmental studies of cell differentiation in the epidermis of monocotyledons. III. Interaction of environmental and genetic factors on stomatal differentiation in three genotypes of barley.

Abstract Seedlings of three genotypes of barley, Atlas 46, Atlas 57 (smooth awned), and Vaughn were grown in the dark under constant temperature conditions, and the intercalary meristem of the first seedling leaf was studied in preparations fixed in Carnoy's fluid and stained in acetocarmine. Using a method previously developed and described in the paper, the amount of irregularity in the succession of stomatal development was estimated, as well as the amount of intercalary meristem present. Irregularity in stomatal succession was significantly higher at 35° than at 20° or 10° C, but over-all irregularity did not differ significantly between varieties. Three types of irregularity were recognized; (A) involving only subsidiary cell formation, (B) involving the division of the guard mother cell to form guard cells, and (C) delay in subsidiary cell formation relative to division of the guard mother cell. Type A was equally frequent in all varieties at all three temperatures; type B was less frequent at 35°, particularly in the Atlas varieties; while type C was much more frequent at 35°, particularly in Atlas. The amount of intercalary meristem in the first seedling leaf was significantly different between varieties at the optimal temperature of 20° and showed significantly more variation in Vaughn and Atlas 57 than in Atlas 46. The conclusion is reached that estimates of variation in the amount of meristematic activity may provide a useful index to variability in growth and yield, or the degree of homeostatic buffering of a variety. Estimates of the irregularity of stomatal formation within a row are valuable chiefly as they contribute to an understanding of stomatal development itself.
The Small Group Context: Designated District Court Judges in the U.S. Courts of Appeals

Decision making in the U.S. courts of appeals occurs primarily in three-judge panels. A substantial number of cases are decided by panels that include a judge who is a district court judge serving temporarily on the appeals bench. This means that court of appeals decision making is often a function of small groups with temporary members. Here, we examine whether designated district court judges behave differently than their court of appeals colleagues when they cast their votes in cases they are deciding as members of three-judge appellate panels. In doing so, we suggest a profitable direction for theory building vis-a-vis judicial decision making. Our analysis of the ideological direction of the votes judges cast, as well as the variance in those votes, indicates that judges on three-judge panels are influenced by the preferences of their fellow panelists, and that designated district court judges, while no more variable than their court of appeals colleagues, are more susceptible to the influence of their peers than are regular members of the courts of appeals in a nontrivial number of cases.
A 0.6 million year record of millennial-scale climate variability in the tropics

A ~600 kyr long scanning X-ray fluorescence record of redox variability from the Cariaco Basin, Venezuela, provides insight into rapid climate change in the tropics over the past five glacial-interglacial cycles. Variations in the sediment accumulation of the redox-sensitive element molybdenum (Mo) can be linked to changes in Intertropical Convergence Zone migration and reveal that millennial-scale variability is a persistent feature of tropical climate over the past 600 kyr, including during periods of interglacial warmth. This new record supports the idea that high-frequency tropical climate variability is not controlled solely by ice volume changes, with implications for the role of high-latitude forcing of Intertropical Convergence Zone position and tropical hydrology on millennial timescales.
THE RECRUIT'S FIRST YEAR

Excerpt Since the birth of our nation and the formation of a defensive army to protect our shores, it has forever been foremost in the minds of our military leaders to stress the point that the art...
Catecholaminergic-cholinergic interaction in the basal forebrain.

Publisher Summary The basal forebrain cholinergic projection system (BFC) has been the focus of considerable attention as a result of evidence implicating it in a number of behavioral functions, including arousal, sensory processing, motivation, emotion, learning, and memory. Cholinergic projection neurons are distributed across a number of classically defined regions of the basal forebrain and collectively project to the entire cortical mantle, including allocortical areas, such as the hippocampus, the amygdala, and the olfactory bulb. In spite of detailed information, concerning the efferent projections of these neurons, as well as significant recent progress in our understanding of the mechanisms of acetylcholine action in the cortex, relatively little is known about the afferents, which drive BFC neurons. This chapter discusses the recent efforts to identify catecholaminergic inputs to BFC neurons in the rat using this approach. Additional biochemical studies test the effect of specific removal of ascending brainstem catecholaminergic fibers on forebrain choline acetyltransferase (ChAT) activity.
Relationship of Dipicolinic Acid Content in Spores of Bacillus cereus T to Ultraviolet and Gamma Radiation Resistance

Spores of Bacillus cereus T lacking dipicolinic acid showed a statistically significant reduction in resistance to ultraviolet and γ radiation as compared with spores with high dipicolinic acid content.
Case-control analysis of survival outcomes in sinonasal acinic cell carcinoma.

Background Acinic cell carcinoma (AciCC) is an uncommon malignant-epithelial salivary gland cancer. In very rare cases, this tumor may arise from sinonasal subsites, with only 19 cases described in the English-language literature. Methods We performed a retrospective analysis of 18 cases of AciCC, obtained from searching the Surveillance, Epidemiology, and End Results (SEER) database between 1973 and 2009. Results Patient demographics, including age, gender, and race, were similar to AciCC cases found in more common locations. However, all patients had low-grade tumors without regional or distant metastases. Comparing these patients to a stage, grade, and treatment–matched cohort of parotid AciCC, we found a lower 10-year overall survival (52.3%) with no significant difference in disease-specific survival (88.9%). Our meta-analysis of survival from cases in the literature estimated 10-year recurrence-free survival at 92.9%. Conclusion To our knowledge, this is the largest cohort of patients with AciCC reported in the English-language literature. Our results suggest that patients with sinonasal AciCC have excellent disease-specific survival, comparable to matched patients with AciCC in more common salivary gland subsites.
Skin Testing of Guinea Pigs and Footpad Testing of Mice With a New Antigen for Detecting Delayed Hypersensitivity to Cryptococcus neoformans

This study was undertaken to evaluate the potential of a cryptococcal culture filtrate antigen, cryptococcin C184, for detecting delayed hypersensitivity in Cryptococcus neoformans-injected animals. The antigen was tested on guinea pigs which had received saline or C. neoformans and on animals sensitized to Histoplasma capsulatum, Blastomyces dermatitidis, Candida albicans, or Sporothrix schenckii. A delayed-type hypersensitivity response was elicited by cryptococcin C184 in C. neoformans-injected guinea pigs, whereas no indurations or erythemas were seen at 48 h after skin testing of saline controls or heterologously sensitized guinea pigs. Besides being specific for Cryptococcus, the antigen showed a high degree of sensitivity and was reproducible. Footpad tests were conducted with the antigen on mice which had previously received either 10(5) viable C. neoformans cells or saline. Delayed hypersensitivity was indicated in the C. neoformans-injected mice by the increase in thickness of antigen-injected footpads when compared with the saline-injected footpads. In control mice, antigen- and saline-injected footpads were comparable in thickness 24 h after injection. Mice sensitized to B. dermatitidis were footpad tested with C184, and no cross-reactivity was demonstrated.
Yield of CT perfusion for the evaluation of transient ischaemic attack

BackgroundMagnetic resonance diffusion-weighted imaging and perfusion-weighted imaging are able to identify ischaemic ‘footprints’ in transient ischaemic attack. Computed tomography perfusion (CTP)...
Periods of Risk in Childhood for the Development of Adult Obesity — What Do We Need to Learn?

The prenatal period, the period of adiposity rebound and adolescence appear to represent critical periods for the development of obesity that persists into adulthood. Nonetheless, relatively little is known about the extent to which incident obesity at each of these intervals contributes to the prevalence of adult obesity. Similarly, little is known about the mechanisms that operate at each of these critical periods to entrain adult obesity.
Reaction modeling of urethane polyols using fraction primary secondary and hindered‐secondary hydroxyl content

The effect of primary, secondary, and hindered-secondary hydroxyl groups on reactions and temperature profiles of polyurethane gels was investigated and modeled using a computer simulation that simultaneously solves over a dozen differential equations. Using urethane gel reaction temperature profiles of the reference compounds 1-pentanol, 2-pentanol, and Voranol 360 reactivity parameters were determined for reference primary, secondary, and hindered-secondary hydroxyl moieties. The reaction parameters, including Arrhenius constants and heats of reaction, were consistent with previous values reported in literature. The approach of using fractions primary, secondary, and hindered-secondary hydroxyl content to characterize reactivity sets the basis for a powerful approach to simulating/predicting urethane reaction performance with limited data on new polyols and catalysts. This code can be used for all polyols, as the kinetic parameters are based on the fraction primary, secondary, and hindered-secondary alcohol moieties, not the type of the polyol. Kinetic parameters are also specific to catalysts where at least one parameter specific to each catalyst is necessary to simulate the impact of that catalyst. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40388.
Author’s reply to Reynolds

I thank the World Bank for its comment and continued support to those affected by the ongoing Ebola virus crisis in west Africa.1 I would like to clarify the discrepancy between the bank’s figures of total Ebola aid and the estimates cited in my study.2 As stated, my …
Evaluation of a sex-based difference in the pharmacokinetics of digoxin.

Study Objective. To determine whether a sex-based difference in digoxin pharmacokinetics exists in patients receiving long-term digoxin therapy for chronic heart failure or atrial fibrillation. Design. Single-center, retrospective review of medical records. Setting. University-based teaching hospital and outpatient clinic. Patients. Sixty-seven adults (32 men, 35 women) with chronic heart failure or atrial fibrillation who were receiving digoxin therapy. Measurements and Main Results. Serum digoxin concentrations and daily digoxin doses were obtained from patients' medical records. Daily doses were adjusted for patients' actual and ideal body weight and body mass index (BMI). The ratio between the serum digoxin concentration and each of the adjusted daily doses of digoxin was compared between men and women. The mean ± SD serum digoxin concentration was 0.85 ± 0.51 ng/ml for men compared with 1.02 ± 0.51 ng/ml for women. Mean ± SD unadjusted doses of digoxin were 0.180 ± 0.063 and 0.164 ± 0.059 mg/day for men and women, respectively; the difference was not statistically significant. Ratios of serum digoxin concentration to daily digoxin doses did not differ by sex when doses were estimated with actual or ideal weight. Only the ratio of the digoxin concentration to the BMI-adjusted dose was significantly different between men and women (0.14 ± 0.09 and 0.19 ± 0.11, respectively, p<0.05). Conclusion. Sex-based differences in digoxin pharmacokinetics were absent when actual or ideal body weight was used. However, the ratio of serum digoxin concentration to daily digoxin dose adjusted for BMI differed by sex. Because digoxin is distributed to lean body mass, use of the BMI could have overadjusted body weight, leading to inaccurate pharmacokinetic assumptions and calculations. The pharmacokinetics of digoxin do not appear to differ by sex.
Induction of HIF‐1α expression by intermittent hypoxia: Involvement of NADPH oxidase, Ca2+ signaling, prolyl hydroxylases, and mTOR

Sleep-disordered breathing with recurrent apnea (periodic cessation of breathing) results in chronic intermittent hypoxia (IH), which leads to cardiovascular and respiratory pathology. Molecular mechanisms underlying IH-evoked cardio-respiratory co-morbidities have not been delineated. Mice with heterozygous deficiency of hypoxia-inducible factor 1alpha (HIF-1alpha) do not develop cardio-respiratory responses to chronic IH. HIF-1alpha protein expression and HIF-1 transcriptional activity are induced by IH in PC12 cells. In the present study, we investigated the signaling pathways associated with IH-evoked HIF-1alpha accumulation. PC12 cells were exposed to aerobic conditions (20% O(2)) or 60 cycles of IH (30 sec at 1.5% O(2) followed by 5 min at 20% O(2)). Our results show that IH-induced HIF-1alpha accumulation is due to increased generation of ROS by NADPH oxidase. We further demonstrate that ROS-dependent Ca(2+) signaling pathways involving phospholipase Cgamma (PLCgamma) and protein kinase C activation are required for IH-evoked HIF-1alpha accumulation. IH leads to activation of mTOR and S6 kinase (S6K) and rapamycin partially inhibited IH-induced HIF-1alpha accumulation. IH also decreased hydroxylation of HIF-1alpha protein and anti-oxidants as well as inhibitors of Ca(+2) signaling prevented this response. Thus, both increased mTOR-dependent HIF-1alpha synthesis and decreased hydroxylase-dependent HIF-1alpha degradation contribute to IH-evoked HIF-1alpha accumulation. Following IH, HIF-1alpha, and phosphorylated mTOR levels remained elevated during 90 min of re-oxygenation despite re-activation of prolyl hydroxylase. Rapamycin or cycloheximide, blocked increased HIF-1alpha levels during re-oxygenation indicating that mTOR-dependent protein synthesis is required for the persistent elevation of HIF-1alpha levels during re-oxygenation.
Use of solid-phase microextraction to detect and quantify gas-phase dicarbonyls in indoor environments

Abstract Solid-phase microextraction (SPME) was evaluated for the detection and quantification of the gas-phase dicarbonyls, glyoxal (GLY) and methylglyoxal (MGLY). Additionally, polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB), and carbowax/divinylbenzene (CW/DVB) fibers were tested to determine the optimum fiber for detection of these species. GLY and MGLY were derivatized with O -(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA), extracted with SPME from headspace or bag chamber and then analyzed by GC/MS. The PDMS/DVB SPME fiber for on-fiber derivatization and subsequent sampling for gas-phase methylglyoxal provided the optimum combination of analytical reproducibility and sensitivity. Linearity of the calibration curve was achieved across a range of 11–222 μg/m 3 (4–75 ppb).
Noninvasive ventilation in chronic obstructive pulmonary disease

Noninvasive ventilation, referring to the provision of mechanical ventilatory assistance without the need for an invasive airway, has been assuming increasing importance in the management of chronic obstructive pulmonary disease (COPD). Particularly in the acute arena, where a number of randomized, controlled trials have demonstrated the efficacy of noninvasive positive-pressure ventilation (NPPV) in averting the need for intubation, noninvasive ventilation is now seen as the first choice mode of ventilation for the therapy of selected patients suffering from COPD exacerbations. Despite numerous studies spanning decades using different types of nonivasive ventilators and all manner of ventilator regimens, however, the use of noninvasive ventilation for patients with severe stable COPD remains controversial. The following discussion focuses on the use of noninvasive ventilation for patients with severe COPD in the subacute and stable settings, paying little attention to the acute setting. For more information on acute applications, the reader is referred elsewhere. 2,29 The following discussion includes the physiologic bases for the use of noninvasive ventilation in severe COPD, evidence for (or against) efficacy, possible indications and selection guidelines, newer possible uses, and practical application as it applies to patients with COPD.
Hybrid Simulation of Adapte Path Control

Adaptive path control of a two-dimensional maneu ver under lunar attraction is simulated at high speed by a hybrid system comprising general-purpose analog and digital computers and programmable parallel logic and conversion components. The opti mization criterion selected leads to both on-off and continuous control variables. The digital computer performs a high-precision simulation of the rocket motion and transmits velocity and position informa tion to the analog computer at small time intervals. The analog, after each information transfer, solves a boundary value problem by high-speed iteration to obtain the optimum thrust control functions, trans ferring back to the digital computer only that portion of the control functions which is needed until the next information transfer. For any perturbation in the data—such as changes in the goal, the optimiza tion criterion, or operating characteristics of the rocket—a new optimum control will be calculated immediately and the system will adjust. The effectiv...
Unstable systems stabilizing each other through adaptation

An asymptotically stable reference model plays a crucial role in the entire literature on adaptive systems. Given a plant with unknown parameters, the objective is to adapt the parameters of a controller so that the behavior of the controlled plant emulates that of the reference model in some sense. This paper addresses the following question, which is markedly different from that encountered in conventional adaptive control: “Can two or more unstable plants adaptively stabilize each other? ”. This is because neither system has a stable model to emulate, and each depends upon the other to stabilize itself. It is not surprising that this seemingly innocuous question has far reaching implications in widely different fields such as biology, psychology, economics and robotics, where it is found to arise frequently. If simple rules of adaptation were adequate to answer the above question, it would not merit much attention. However, preliminary investigations have revealed that such adaptation often does lead to instability. In fact the answer to the question is far from simple, and depends upon the assumptions made regarding the adaptive subsystems, and the manner in which they interact with each other. This has given rise to a vast spectrum of interesting questions. The objective of this paper is consequently not to provide an exhaustive set of answers, but merely to pose several problems in what the authors hope will be a new area of research, and to present preliminary results concerning some of them.
Single-unit analysis of binocular neurons in the frog optic tectum.

Abstract Responses of single, postsynaptic neurons in the deeper cellular layers of the frog optic tectum were recorded with glass-coated metal microelectrodes. Particular emphasis was placed upon the analysis of input and response properties of binocularly driven neurons. Section of the posterior and tectal commissures did not affect binocular response activity. However, removal of the contralateral tectal lobe or section of the deep tegmental commissures eliminated the ipsilateral component of binocular unit activity. The pathway of visual information from the ipsilateral retina is probably via the contralateral tectum, through the tegmental commissures to the ipsilateral tectum. The majority of tectal neurons observed could be activated by visual, tactile, and occasionally, auditory stimuli. Such multisensory units showed a spontaneous level of activity, whereas purely visual neurons did not. Visual receptive fields of binocular neurons were larger than those of monocular neurons in the intact preparation. Tectal neurons responded only to moving stimulus targets and often showed rapid adaptation to a repeated stimulus. However, some units showed little stimulus adaptation and the majority of units observed fell between those two extremes. Tectal neurons showed a greater response to vertical than to horizontal stimulus motion, which may be related to the predominance of vertical eye movements in the frog.
Validating molecular markers for barley leaf rust resistance genes Rph5 and Rph7

Leaf rust, caused by Puccinia hordei, is a serious threat to barley (Hordeum vulgare L.) production. Genes Rph5 and Rph7 confer resistance to many of the most prevalent races of P. hordei in the United States and Europe, respectively. The reliability and diagnostic capabilities of several molecular markers for these two genes were evaluated and validated for use in gene postulation, marker-assisted selection (MAS) and eventual pyramiding of genes Rph5 and Rph7 with other effective resistance genes. Fifty-eight winter barley experimental lines developed at Virginia Polytechnic Institute and State University, as well as seven barley cultivars were phenotyped for reaction to three diverse isolates of P. hordei and genotyped with molecular makers closely linked to genes Rph5 and Rph7. Sequence tagged site markers TC2863-12.4 and ABG70 as well as simple sequence repeat marker AY642926-CA11 were reliable and diagnostic in gene postulation and have potential for use in MAS and pyramiding of genes Rph5 and Rph7. Comparison of phenotypic and genotypic data revealed that one barley line VA04H-95 has genes Rph5 and Rph7 and at least one unknown gene.
A new type of neutron spectrometer

Abstract Neutrons are detected in a small Li6I(Eu) scintillator placed at the center of polyethylene moderating spheres with sizes ranging from 2 to 12 inches in diameter. The efficiency of this neutron counter has been experimentally determined using monoenergetic neutrons from thermal energies to 15 MeV. The counter has excellent energy sensitivity from 0.1 to 2 MeV and is particularly useful for determining the shapes of continuous neutron spectra. The pronounced difference in the efficiencies for the five sizes of spheres which have been calibrated provides a basis for accurate neutron energy determination. The good γ ray discrimination of the counter allows it to be used with a radium-beryllium neutron source. Neutron spectra from a variety of sources have been determined with this counter. These include the two groups of neutrons from the C14(p,n)N14 reaction, the evaporation spectrum of the neutrons from the reaction Rh103(p,n)Pd103, the energy spectra of inelastically scattered neutrons, and the neutron spectrum from the scattering of fast neutrons by the floor and walls of a building.
INVESTIGATION OF THE USE OF LASER-DOPPLER VELOCIMETRY IN TWO-PHASE BUBBLY FLOWS

Understanding the dynamic phenomena of viability loss of shear sensitive cells and bubble breakage and coalescence within airlift reactors requires knowledge of local, liquid-phase hydrodynamics. The laser-Doppler velocimeter (LDV) is a non-invasive instrument which may be used to obtain this information. Experimental procedures and software were developed to detect and measure Doppler bursts in two-phase flow in a split-cylinder airlift reactor. Off-line analysis of the data indicated a detection rate approximately one order of magnitude greater than that observed using an available commercial frequency tracker. Approximately 400 to 500 observations are needed for the ensemble mean to characterize the local mean velocity to within ±5% for a superficial gas velocity of 10.4 cm/s, the highest superficial gas velocity used in these studies. The limitations, prospects, and signal-processing options for LDV in this application are also discussed
Biliary scintiscanning in suspected acute cholecystitis

The value of biliary scintiscanning in the early diagnosis of suspected acute cholecystitis was studied in 50 patients. All the patients had clinical features and laboratory data suggestive of acute cholecystitis. Scintigraphy was performed using99mTc HIDA and BIDA and the results were compared to oral cholecystography (OCG) and ultrasonography (US). Nineteen patients were proven at operation and at subsequent histologic examination to have had acute cholecystitis, while the other 31 had different conditions. The scan was 100% sensitive and 96% accurate, while OCG was sensitive in 93% and accurate in 86% in this group. US was not very useful in our experience. Scintiscanning could be performed in the acute stage even in the presence of vomiting and jaundice and was not associated with any adverse reactions. It is very valuable in the diagnosis of patients with suspected acute cholecystitis.
ON A HYPERBOLIC–PARABOLIC SYSTEM MODELING CHEMOTAXIS

We investigate local/global existence, blowup criterion and long-time behavior of classical solutions for a hyperbolic–parabolic system derived from the Keller–Segel model describing chemotaxis. It is shown that local smooth solution blows up if and only if the accumulation of the L∞ norm of the solution reaches infinity within the lifespan. Our blowup criteria are consistent with the chemotaxis phenomenon that the movement of cells (bacteria) is driven by the gradient of the chemical concentration. Furthermore, we study the long-time dynamics when the initial data is sufficiently close to a constant positive steady state. By using a new Fourier method adapted to the linear flow, it is shown that the smooth solution exists for all time and converges exponentially to the constant steady state with a frequency-dependent decay rate as time goes to infinity.
Nature's plumbing

Geysers and Geothermal Energy. By John S. Rinehart. Pp. 223. ISBN 3-540-90489-1. (Springer-Verlag: 1981.) $22.50, DM 38. Geothermal Resources: An Energy Alternative. By Harsh K. Gupta. Pp. 227. ISBN 0-444-41865-2. (Elsevier Scientific: 1981.) $61, Dfl. 125. Geothermal Systems: Principles and Case Histories. Edited by L. Rybach and L.J.P. Muffler. Pp. 359. ISBN 0-471-27811-4. (Wiley: 1981.) £22, $52.25. Geothermal Systems. By John Elder. Pp. 508. ISBN 0-12-236450-3. (Academic: 1981.) £20.60, $49.50.
Interorganizational trust in B2B relationships

While research about trust in B2C relationships appears to be flourishing, we contend that trust in B2B relationships remains underexplored. As the first step toward the remedy of this, we conducted a review of studies in which trust in B2B relationships has been covered, albeit to varied extents. We found that, contrary to the authors' and our expectation, there appeared to be a set of common characteristics among the definitions of trust in those studies. We explored in depth five key dimensions of trust that have been discussed most frequently. They reflect the richness of the concept of trust in B2B relationships. Since, within the context of B2B, trust should not be viewed separately from technologies, we discussed the conceptualizations with which technologies may be viewed as related to trust in B2B. We found that IT has been most commonly viewed either as a tool or nominally. The time factor of trust also is discussed, followed by our conclusion on the commonalities and gaps among the current studies on trust in B2B relationships.
Disorganisation of quantal acetylcholine release by zinc at the Torpedo nerve-electroplate junction

The effects of zinc (Zn2+) on quantal acetyl-choline release at the Torpedo nerve-electroplate junction were analysed by using loose patch electrodes designed to record evoked and spontaneous electroplate currents in a delimited area (electrode diameter of 10–15 μm) of the synaptic region. Zn2+ reduced the amplitude, prolonged the synaptic delay and slowed down the rising phase of all-or-none electroplate currents (EPCs) generated in response to activation of Na+ channels in a preterminal nerve branch. In graded EPCs (generated in response to direct activation of terminal Ca2+ channels), Zn2+ caused a reduction of quantal content but no change in the quantal size or in the minimum synaptic delay. The rise time of graded EPCs was prolonged but their half-decay time was not affected. Miniature EPCs (MEPCs) in control preparations had a widely distributed amplitude distribution but a homogeneous and rapid time course. Conversely, MEPCs in Zn2+-treated tissue exhibited a homogeneous and small amplitude, but a prolonged and more variable time course. Zn2+ at 1 mM caused, by itself, a high occurrence of MEPCs under conditions (flat-edged electrodes) when MEPCs are normally very infrequent. It is concluded that Zn2+ can both activate and inhibit the release mechanism and Zn2+-induced quanta exhibit an abnormal time course. The activation of the release process by Zn2+ or by Ca2+ may result in the production of quanta with different kinetics.
Mechanical properties of particulate-reinforced aluminum-matrix composites

Abstract Fracture toughness and tension tests were performed on two aluminum alloy matrices, 2014-O and 2024-O reinforced with alumina particulates of different volume fractions and particulate sizes. The results indicated that the yield strength increased with decreasing particle spacing. The fracture toughness increased with increasing particle spacing provided that the particle size was less than a limiting value, above which unstable crack growth occurred and the toughness lowered. Although these composites exhibited limited ductility on a macroscopic scale, fractography revealed that fractured occurred by a locally ductile mechanism.
Bond alternation, on-site Coulomb correlations, and solitons in polyacetylene

We explore the effect of including electronic on-site Coulomb correlations on the energy of solitons in polyacetylene within an unrestricted Hartree-Fock calculation for finite chains. For parameters characteristic of polyacetylene, we find that the conjugated non-magnetic ground state occurs only when the strength of the on-site electronic repulsion ($U$) is less than 4.66 eV. For this range of $U$ no significant changes occur in soliton energies and widths upon inclusion of on-site electronic repulsion.
Theory and Practice of Free Food in Hospitals: A Guide for the Hungry Hospitalist

Anyone who has spent time in an American hospital must have noticed the abundance of free food. Whether breakfast at morning Grand Rounds, a drug representative teaching conference, or a potluck meal in the nursing lounge, free food is ubiquitous. Over the span of 2 decades, much work has been done in the bourgeoning field of hospital medicine, but this subject has been starved of attention. I offer this essay to serve up this neglected topic. Clinicians have long recognized the importance of food in medicine. Hippocrates noted, “It is easier to fill up with drink than with food.”1 Handy advice when considering what to eat. Unfortunately, Hippocrates lived millennia before development of the hospital, and we cannot know how profound his thoughts on free food at seminars, meetings, and nursing stations would have been. Not surprisingly, free food is popular in hospitals, but topical contemporary scholarship is limited. A recent covert surveillance study found that a box of chocolate on a hospital ward was opened within 12 minutes, and the median chocolate survival time was 51 minutes. Physicians were the third largest chocolate consumers after health care assistants and nurses.2 Although popular, the efficacy of supplying free food as an incentive to influence physician behavior is not …
Experiences in implementing a studio component into a course for novice web developers

This paper discusses an educational experience aimed at producing better computer-based projects by including in the assessment process an art appreciation-like critique component. In a way that at times parallels the constructive criticism of work done by art students we asked our participants to critique their classmates as well as themselves. New elements of assessment such as aesthetics, user-engagement, naturalness, completeness, and unrealized potential of the projects appeared in the discourse. Although it is very early to extrapolate results, our conclusion is that a noticeable improvement of the overall quality of the final products as well as a higher level of collaboration, participation, and student satisfaction resulted from this approach.
Is a little hypoxia good for you

Comment on Perrotta et al, page [514][1] In this issue, Perrotta and colleagues from the Second University of Naples report on their finding of endemic congenital polycythemia due to homozygous VHL 598C > T on the Italian island of Ischia. The condition leads to increased expression of HIF-1, the
Two new oro-cervical radiographic indexes for chronological age estimation: a pilot study on an Italian population

Abstract Chronological age (CA) plays a fundamental role in forensic dentistry (i.e. personal identification and evaluation of imputability). Even though several studies outlined the association between biological and chronological age, there is still great variability in the estimates. The aim of this study was to determine the possible correlation between biological and CA age through the use of two new radiographic indexes (Oro-Cervical Radiographic Simplified Score – OCRSS and Oro-Cervical Radiographic Simplified Score Without Wisdom Teeth – OCRSSWWT) that are based on the oro-cervical area. Sixty Italian Caucasian individuals were divided into 3 groups according to their CA: Group 1: CAG 1 = 8–14 yr; Group 2: CAG 2 = 14–18 yr; Group 3: CAG 3 = 18–25 yr; panorexes and standardised cephalograms were evaluated according Demirjian's Method for dental age calculation (DM), Cervical Vertebral Maturation method for skeletal age calculation (CVMS) and Third Molar Development for age estimation (TMD). The stages of each method were simplified in order to generate OCRSS, which summarized the simplified scores of the three methods, and OCRSSWWT, which summarized the simplified DM and CVMS scores. There was a significant correlation between OCRSS and CAGs (Slope = 0.954, p R -squared = 0.79) and between OCRSSWWT and CAGs (Slope = 0.863, p R -squared = 0.776). Even though the indexes, especially OCRSS, appear to be highly reliable, growth variability among individuals can deeply influence the anatomical changes from childhood to adulthood. A multi-disciplinary approach that considers many different biomarkers could help make radiological age determination more reliable when it is used to predict CA.
Bobble-head doll syndrome due to trapped fourth ventricle and aqueduct

The bobble-head doll syndrome has been associated with third ventriculomegaly due to cysts or aqueductal stenosis. A case is described in which the aqueduct and fourth ventricle are enlarged, but the third ventricle is not. The unifying pathogenesis for this and previous cases is pressure on the dorsomedial red nucleus.