cssi/SciSciGPT-SciSciNet huggingface dataset:
Chapter 22 Separation chemistry

Publisher Summary This chapter discusses recent progress in means of isolating individual lanthanides and yttrium. The chapter discusses well-developed processes for the preliminary treatment of rare earth mixtures. The lanthanides comprise a series of inner-transition elements in which the number of 4-f electrons increases from 1 to 14. The main effect of increasing the number of electrons in this internal energy sublevel, as the nuclear charge increases, is to gradually decrease the cationic radius of consecutive Ln3+ ions, so that they range in size from that of La3+ to that of Sc3+. Because of the remarkable similarities in their cationic charge and their radii, lanthanons form many isomorphic series of compounds, and are always found as complex mixtures (not always of exactly the same composition) in rocks and minerals that comprise the earth's crust. The problem of separating them by reactions in aqueous media is aggravated further by the fact that increased charge density, which accompanies lanthanide contraction, promotes a greater overall degree of aquation and renders individual hydrated cationic radii even more similar.
The quality of clinical trials published in The Journal of Family Practice, 1974-1991.

BACKGROUND: Previous analyses of published clinical trials have identified major deficiencies in reporting, design, analysis, and overall quality. The purpose of this study was to determine the strengths and weaknesses of published clinical trials in family practice, and to identify predictors of quality in these trials. METHODS: Randomized controlled clinical trials published in The Journal of Family Practice from 1974 to 1991 were eligible for the study. Two raters independently evaluated the adequacy and appropriateness of reporting, design, and analysis for each clinical trial, using the Chalmers index for assessing clinical trial quality. Multiple linear regression was used to determine the predictors of quality. RESULTS: The 53 trials included in the study showed deficiencies in reporting, design, and analysis, although fundamental design issues, such as blinding, were a relative strength. On average, the trials scored 35% of the possible points on the scale. Three factors were positively associated with overall quality: year of publication, number of pages of the published report, and the type of intervention. Trials with pharmacologic and non-medication therapy interventions, such as diet, had higher quality scores than did trials with psychosocial or educational interventions. CONCLUSIONS: The overall quality of these clinical trials was less than optimal but comparable to previously analyzed groups of trials. The improvement in quality over time may be related to improvement in the quality of the trials themselves, or more exacting editorial standards, or a combination of the two.
Antagonists of PD-1 and PD-L1 in Cancer Treatment

The PD-1 pathway, comprising the immune cell co-receptor Programmed Death 1 (PD-1) and its ligands, PD-L1 (B7-H1) and PD-L2 (B7-DC), mediates local immunosuppression in the tumor microenvironment. Drugs designed to block PD-1 or PD-L1 "release the brakes" on anti-tumor immunity and have demonstrated clinical activity in several types of advanced cancers, validating this pathway as a target for cancer therapy. Two such drugs have recently been approved to treat melanoma and lung cancers, and regulatory approvals in first- and second-line settings for additional cancer types are anticipated. The manageable safety profile of PD-1/PD-L1 blocking drugs identifies them as suitable for outpatient administration and the development of combinatorial therapies. Ongoing studies aim to identify biomarkers to guide patient selection, which would further improve the risk:benefit ratio for these drugs.
Organization of Ca2+ Stores in Vascular Smooth Muscle: Functional Implications

Much evidence suggests that caffeine/ryanodine (Caf/Ry)-releasable and inositol-1,4,5-trisphosphate (InsP3)-releasable Ca2+ stores in the sarcoplasmic reticulum (SR) of smooth muscles are at least partially distinct. We directly visualized SR stores in primary-cultured rat mesenteric artery myocytes with high-resolution digital imaging and the low-affinity Ca2, indicator, Furaptra (Kd = 75.6 microM). The SR appears to be a continuous tubular network. Nevertheless, SR Ca2+ stores are organized into small, separate, functionally independent compartments. Cyclopiazonic acid (CPA; inhibits SR (Ca2+ pump) and Caf (or Ry) release Ca2+ from different, spatially distinct compartments. Similar heterogeneity is seen with serotonin (acts via InsP3), which unloads only the CPA-sensitive compartments. Some of the SR ('junctional' SR; jSR) lies within 12-15 nm of the plasmalemma (PL). The jSR, the overlying PL microdomains, and the intervening, tiny volume of cytosol form junctional complexes ('PLasmERosomes'). Na+ pumps with high-ouabain-affinity alpha2 or alpha3 subunits, Na+/Ca2+ exchangers, and store-operated channels are confined to these PL microdomains, whereas Na+ pumps with low-ouabain-affinity alpha1 subunits and plasma membrane Ca2+ pumps are uniformly distributed. As a result of this organization, low-dose ouabain can selectively modulate Na+ and Ca2+ concentrations in the PLasmERosomes and jSR Ca2+ stores, and can thereby regulate Ca2+ signalling.
Effect of protein quality on vitamin B-6 status in the rat.

Although it is well established that the requirement for vitamin B-6 is increased by high levels of dietary protein, little is known regarding the effect of protein quality on this requirement. We therefore compared the effect on vitamin B-6 status of diets containing amino acid mixtures equivalent to low quality (LQ) or good quality (GQ) protein. The effect of protein quality was tested at two levels of vitamin B-6, 0.2 and 7.0 mg/kg diet. Food intake was controlled by pair-feeding so that no statistically significant difference in food intake existed among the groups. After 6 weeks, vitamin B-6 status was evaluated by determining urinary 4-pyridoxic acid, plasma pyridoxal phosphate and total vitamin B-6 in liver. At both levels of vitamin B-6 intake, mean values for all three indices of vitamin B-6 status were lower in rats fed LQ protein than in rats fed GQ protein, but these differences were not statistically significant (Scheffe's multiple-range test). However, a strong and highly significant linear relationship (P less than 0.0001) existed between the mean values for each parameter of vitamin B-6 status and protein quality--specifically, LQ protein appeared to have an adverse effect on vitamin B-6 status of rats fed either suboptimal or ample vitamin B-6. These results suggest a minor but consistent deleterious effect of LQ protein on vitamin B-6 status in rats, regardless of vitamin B-6 intake.
Alexander M. Kellas and the physiological challenge of Mt. Everest

Alexander M. Kellas (1868–1921) was a British physiologist who made pioneering contributions to the exploration of Everest and to the early physiology of extreme altitudes, but his physiological contributions have been almost completely overlooked. Although he had a full-time faculty position at the Middlesex Hospital Medical School in London, he was able to make eight expeditions to the Himalayas in the first two decades of the century, and by 1919 when the first official expedition to Everest was being planned, he probably knew more about the approaches than anybody else. But his most interesting contributions were made in an unpublished manuscript written in 1920 and entitled “A consideration of the possibility of ascending Mount Everest.” In this he discussed the physiology of acclimatization and most of the important variables including the summit altitude and barometric pressure, and the alveolar Po2, arterial oxygen saturation, maximal oxygen consumption, and maximal ascent rate near the summit. On the basis of this extensive analysis, he concluded that “Mount Everest could be ascended by a man of excellent physical and mental constitution in first-rate training, without adventitious aids [supplementary oxygen] if the physical difficulties of the mountain are not too great.” Kellas was one of the first physiologists to study extreme altitude, and he deserves to be better known.
Optical carry-free addition and borrow-free subtraction based on redundant signed-digit numbers

A single-step electro-optical or two-step all optical carry-free addition and borrow-free subtraction units are designed using a new recoding algorithm for the signed-digits redundant numbers. A new recording truth-table which has a symmetrical complemented relationship between the input minterms (entries that produce an output of 1 or 1) and their corresponding output bits is developed. Using the new recording scheme, an efficient adder/subtracter units are implemented using optical symbolic substitution based content-addressable memory (CAM). It is shown that the new recoded signed-digit based adder/subtracter has much less symbolic substitution rules and its superiority is established over all other two-step based-symbolic substitution optical implementations. >
Homotopy equivalences of 3-manifolds and deformation theory of Kleinian groups

Introduction Johannson's characteristic submanifold theory Relative compression bodies and cores Homotopy types Pared 3-manifolds Small 3-manifolds Geometrically finite hyperbolic 3-manifolds Statements of main theorems The case when there is a compressible free side The case when the boundary pattern is useful Dehn flips Finite index realization for reducible 3-manifolds Epilogue Bibliography Index.
Griffiths effects in random Heisenberg antiferromagnetic S = 1 chains

I consider the effects of enforced dimerization on random Heisenberg antiferromagnetic $S=1$ chains. I argue for the existence of novel Griffiths phases characterized by two independent dynamical exponents that vary continuously in these phases; one of the exponents controls the density of spin-1/2 degrees of freedom in the low-energy effective Hamiltonian, while the other controls the corresponding density of spin-1 degrees of freedom. Moreover, in one of these Griffiths phases, the system has very different low temperature behavior in two different parts of the phase which are separated from each other by a sharply defined crossover line; on one side of this crossover line, the system ``looks'' like a $S=1$ chain at low energies, while on the other side, it is best thought of as a $S=1/2$ chain. A strong-disorder renormalization group analysis makes it possible to analytically obtain detailed information about the low temperature behavior of physical observables such as the susceptibility and the specific heat, as well as identify an experimentally accessible signature of this crossover.
Pyromellitic Diimides: Minimal Cores for High Mobility n-Channel Transistor Semiconductors

Three pyromellitic diimides were synthesized in high yields by one conventional reaction between pyromellitic dianhydride and various amines. The films made from these pyromellitic diimides derivatives exhibit a mobility up to 0.079 cm2/(V.s). In addition, the on/off ratios of n-channel devices are as high as 1 000 000.
Measurement Bias Across Gender on the Children's Depression Inventory Evidence for Invariance From Two Latent Variable Models

Confirmatory factor analysis for ordered-categorical measures (CFA-OCM) and rating scale item response theory (IRT) analyses explore measurement bias across gender on the Children's Depression Inve...
Biological and pharmacological significance of the expanded S-outer shell in electron transfer reactions.

Die Dihydrosulfoxidgruppe wird als potentielle Wirkungsgruppe fur die Photolyse von Wasser zur Diskussion gestellt. Die Moglichkeiten der Elektronenubertragung von Cytochromdihydrosulfoxid werden erwogen.
Differences by sex in cardiovascular disease in Williams syndrome.

Objective: To analyze the incidence and severity of cardiovascular disease in patients with Williams syndrome (WS) and to identify factors contributing to its variable expression. Methods: Clinical data on patients with WS were collected from several WS centers. Elastin gene deletions were confirmed in all patients. Age at diagnosis, growth data, and cardiovascular diagnoses were recorded retrospectively. Cardiac diagnoses were made on the basis of echocardiographic data. The severity of supravalvular aortic stenosis was recorded by using a 4-step scale (none, mild, moderate, severe). Results: Statistical analysis of the data revealed that the severity of both supravalvular aortic stenosis and total cardiovascular disease was significantly greater in male patients than female patients (P < .002 and P < .002, respectively; Kruskal-Wallis rank-sum test). This difference was not accounted for by differences in height, weight, body mass index, or head circumference. The clinical diagnosis of WS was made at a significantly younger age in male patients (P < .01, Student t test). Earlier diagnosis was partly because of increased incidence and severity of cardiovascular disease. Another determinant of early diagnosis was low body mass index. Conclusion: Penetrance and severity of the elastin arteriopathy in patients with WS is affected by sex. We hypothesize that differences by sex in arterial stenoses may be related to prenatal hormonal effects. Future epidemiologic and in vitro studies may provide additional insight into the pathogenetic mechanisms of these observed differences. (J Pediatr 2001;139:849-53)
Nonresonant two-photon pulsed field ionization studies of organosulfur molecules and radicals

The study of molecular photoionization by high resolution photoelectron (PE) spectroscopy hasbeen most valuable for understanding detailed photoionization dynamics and for obtaining accuratespectroscopic and energetics information about neutral and ionic species.' However, the typical energyresolution of 5-25 meV available for conventional PE spectroscopic techniques is insufficient forobtaining rotationally and vibrationally resolved PE spectra of polyatomic species. With the recentdevelopment of the laser pulsed field ionization (PH)2 method, a version of the zero-kinetic-energy(ZEKE) PE technique,34 the energy resolution for PE detection has improved to sub-wavenumbers,approaching that achieved in optical spectroscopy. Rotationally and vibrationally resolved PFI-PEspectra have been reported for many diatomic molecules, such as 02 (Refs. 5-7), N2 (Ref. 9), NO (Refs.
Light-Scattering Functions and Particle-Scattering Factors for Ellipsoids of Revolution*

Light-scattering functions and particle-scattering factors from Rayleigh–Gans theory have been computed for ellipsoids of revolution having the axial ratios: 0, 14,1/22,12,1/2, 1, 2, 2, 22, 4, ∞.
A comparison of dynamic characteristics of fluconazole, itraconazole, and amphotericin B against Cryptococcus neoformans using time-kill methodology

Abstract This study evaluated the in vitro pharmacodynamics of fluconazole, itraconazole, and amphotericin B against Cryptococcus neoformans . MICs were determined for three clinical isolates according to NCCLS guidelines (M27). Time-kill studies were performed using antifungal concentrations of 0.25-32xMIC and inocula of 10 3 and 10 5 CFU/ml. At predetermined time points over 72 hours, samples of each inoculum/drug combination were withdrawn and plated using a spiral plater. Colony counts were determined after incubation at 35°C for 48 hours. Area under the kill curves (AUKCs) were plotted versus the AUC/MIC ratios. Inoculum effect was evaluated by calculating an estimated AUKC for the low inoculum then comparing it to the measured low inoculum using the unpaired Student's t-test. The MICs of fluconazole and itraconazole for isolate 97-1199, 97-1061, and 97-585 were 2, 4, 32μg/ml and 0.03, 0.06, 0.5μg/ml, respectively. For amphotericin B, the MIC was 0.25μg/ml for each isolate. The triazoles demonstrated fungistatic activity against each isolate at both inocula with the exception of itraconazole against C. neoformans 97-585. Maximal suppression was noted at concentrations 8-16xMIC correlating with an AUC/MIC of 192 for both inocula. Conversely, amphotericin B was fungicidal and displayed concentration-dependent activity against each isolate at both inocula. Maximal killing was observed at concentrations >4xMIC for the low inoculum and >8xMIC for the high inoculum for each isolate. No statistically significant differences were detected between the measured and estimated AUKCs for each antifungal agent. In conclusion, our results suggest that the triazoles were most effective against C. neoformans when concentrations were maintained at 8-16xMIC. Amphotericin B, on the other hand, was concentration-dependent; thus, greater activity was exerted at higher concentrations.
The crisis in primary care and the role of medical schools. Defining the issues.

THE HEALTH care theme of the mid-1960s was insufficient physician supply, and the need to increase medical school enrollment was endorsed by many. Both federal and state legislators provided considerable financial incentives to schools to increase their enrollments and to prospective medical students to defray the costs of their medical education through low-interest loans. As a result, new first-year enrollments at US medical schools rose from 8483 in 1961 to 16103 in 1986 and have been maintained essentially at this level, with only a slight decrease in 1990 to 15998.1 In 1980, the publication of the Summary Report of the Graduate Medical Education National Advisory Committee raised for the first time the question of whether, with the exception of primary care physicians, we were training far more physicians than were needed.2A future "physician glut" became commonly assumed. Over the last several years, the accuracy of this prediction
Production of Elemental Nitrogen by Certain Mammals including Man

Experiments involving man and other mammals have shown that some food nitrogen can be converted to nitrogen gas. This gas is produced in quantities sufficient to balance the nitrogen equation.
The k-in-a-row up-and-down design, revisited

The percentile-finding experimental design known variously as ‘forced-choice fixed-staircase’, ‘geometric up-and-down’ or ‘k-in-a-row’ (KR) was introduced by Wetherill four decades ago. To date, KR has been by far the most widely used up-and-down (UD it is implemented most commonly in sensory studies. However, its statistical properties have not been fully documented, and the existence of a unique mode in its asymptotic treatment distribution has been recently disputed. Here we revisit the KR design and its basic properties. We find that KR does generate a unique stationary mode near its target percentile, and also displays better operational characteristics than two other U&D designs that have been studied more extensively. Supporting proofs and numerical calculations are presented. A recent experimental example from anesthesiology serves to highlight some of the ‘up-and-down’ design family's properties and advantages. Copyright © 2009 John Wiley & Sons, Ltd.
Issues for the international community 1978

Progress in the restructuring of economic relations between developing and industrial countries has been insignificant in recent years and the current international economic situation is characterized by sluggishness of growth, intensifying protectionist pressures and persistent international monetary instability. Against this background the following article explains the tasks facing the international community in 1978 from UNCTAD’s point of view.
Sensitive detection of GM1 lipid rafts and TCR partitioning in the T cell membrane

Abstract The cholesterol-rich lipid rafts on T cell membrane play important role in the formation of T cell receptor (TCR) signalosome upon receptor ligation. Analytical studies on the kinetics of lipid rafts formation and recruitment of protein receptors to lipid rafts are still limited by the use of a large number of cells. Herein, we describe a strategy for detecting fine alterations in the amount and distribution of glycosphingolipid (GM1) lipid rafts, and in the formation of GM1–TCR complexes in detergent-insoluble and -soluble compartments of the T cell membrane from a relative low number of cells. Using this strategy, we found that the GM1 moiety was physically associated with TCR in both detergent-insoluble and -soluble fractions. Shortly after ligation of CD3/TCR complex with a soluble CD3-e mAb, the TCR was found mainly in the detergent-soluble fraction of the T cell membrane.
Phytoplankton-Group Specific Quantitative Polymerase Chain Reaction Assays for RuBisCO mRNA Transcripts in Seawater

The gene for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) has been shown to be a useful target for molecular assays that quantify form- or clade-specific RNA transcript concentrations as a proxy for the carbon fixation activity of marine phytoplankton. To improve the phylogenetic specificity and sensitivity of RNA probe hybridization methods, a quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay has been reported for diatom and pelagophyte rbcL RNA. Here we detail enhancements made to this PCR method and development of additional assays to specifically quantify rbcL expression from haptophytes, Synechococcus and high-light Prochlorococcus. In vitro RNA transcripts were tested to demonstrate specificity and quantitative accuracy. Application of these methods on seawater samples from two depth profiles in the northern Gulf of Mexico showed a fair degree of agreement between PCR and hybridization results, with results for the chromophytic or form ID rbcL-containing organisms having better agreement between the two methods. Diatoms and other heterokonts were shown to be the primary carbon fixers at these locations by PCR, in agreement with greater form ID rbcL RNA measured by hybridization.
Provider assessment of eligibility for hepatitis C treatment in HIV-infected homeless and marginally housed persons

Purpose: To characterize the group of providers delivering medical care to HIV and hepatitis C (HCV) co-infected homeless and marginally housed individuals in San Francisco and to assess factors affecting provider decisions to initiate HCV treatment in this population. Subjects and methods: The Research in Access to Care for the Homeless (REACH) cohort is a representative sample of HIV-infected homeless and marginally housed individuals identified from single room occupancy hotels, homeless shelters and free lunch programs in San Francisco. Primary care providers (PCP) for active, HIV/HCV co-infected REACH cohort participants were administered face-to-face, semi-structured interviews. REACH participants were administered quarterly face-to-face structured interviews. Results: 52/62 (83.9%) providers were interviewed regarding 133/155 (85.8%) active, HIV/HCV co-infected patients. Providers classified 94/133 (70.7%) patients as ineligible for HCV treatment. The mean number of reasons for ineligibility was 3.2. Most frequent reasons for provider determination of ineligibility included likelihood of poor medication adherence, depression, active injection drug use and patient disinterest in treatment. In addition, structural barriers to treatment included poor access to testing, delays in evaluation by a gastroenterologist and exclusion from treatment of patients with comorbidities. Conclusions: While HCV infection is common, HCV treatment is rare in the HIV/HCV coinfected urban poor. On average, the PCP in this study are experienced and are familiar with this patient population. There are many reasons for providers classifying patients as ineligible for HCV treatment. While these reasons indicate that treatment is difficult given chaotic lifestyle and concurrent medical conditions of this population, they are not insurmountable barriers. New treatments and strategies are necessary to treat this population with high rates of hepatitis C infection.
Coherence and Consistency of Investors' Probability Judgments

This study investigates the quality of direct probability judgments and quantile estimates with a focus on calibration and consistency. The two response modes use different measures of miscalibration, so it is difficult to directly compare their relative (in)accuracy. We employed a more refined within-subject design in which decision makers (DMs) used both response modes to make judgments about a random sample of stocks accompanied by identical information to facilitate comparison between the two judgment methods. DMs judged the probabilities that the stocks will reach a certain threshold, provided lower and upper bounds of these forecasts, and estimated median, 50%, 70%, and 90% confidence intervals of their future prices. We found that the judgments were internally consistent and coherent, but in most cases they were slightly miscalibrated. We used several new methods of analysis that allow for more precise and reliable comparison between the two response modes. We inferred point probability estimates for the target events from the confidence intervals and analyzed them by the same methods applied to binary judgments. Interestingly, when we quantified miscalibration in identical fashion for both methods we did not find evidence of differential levels of miscalibration for the probability judgments and the confidence intervals. We discuss the theoretical and practical implications of these results.
Mechanisms of thermo-solutal transport and segregation in high-pressure liquid-encapsulated Czochralski crystal growth

The mechanism of dopant transport and segregation in high-pressure liquid-encapsulated Czochralski (HPLEC) grown III-V compound crystals (e.g., GaAs, InP) has been numerically studied using an integrated model, MASTRAPP. The model approximates the melt flow in the crucible as a quasi-steady-state, laminar, and axisymmetric flow, but the gas flow is considered as turbulent. Based on the physics of the growth process, a two-time-level scheme has been implemented where the dopant transport and growth are simulated at a smaller time scale while flow and temperature solutions are obtained from quasi-static calculations. Detailed numerical analyses are performed for the conditions of pure crystal rotation, pure thermally driven natural convection, and pure crucible rotation as well as for mixed flow with all of these forces present simultaneously. The dopant transport and segregation in these cases are well correlated to the corresponding melt flow pattern. Very weak radial segregation is predicted for pure crystal rotation because the resulting melt flow leads to a fairly flat solute boundary layer. The natural convection, on the other hand, produces a nonuniform boundary layer along the melt/crystal interface. This leads to a strong radial segregation with a high concentration along the central axis of the crystal. The crucible rotation has a similar effect. The combined effect of all of these flow mechanisms produces a strong radial segregation, whose extent depends on the relative strength of the driving forces. In all of these cases, strong melt flows lead to thin boundary layers that result in decreased longitudinal segregation. The predictions agree well with the experimental observations reported in the literature.
Temptations of the flesch

A Briton's educational level, social class, sex and age all go to determine the degree of linguistic difficulty which he finds acceptable in reading matter. Tables show how these determinants of acceptability relate to readability as measured by word and sentence lengths. It is hypothesised that long sentences are difficult because comprehension depends upon combining cortical patterns evoked by grammatically related elements; but in long sentences the pattern evoked by one element may have decayed before the next related element is read. Long words may cause difficulty because they are generally the more precise words, requiring longer to categorise semantically; but the longer the search for a word's meaning, the more likely that the preceding context will be lost beyond recall.
Translational Research in Breast Cancer

The discovery of 25,000 human genes from the Human Genome Project has had a dramatic impact on the translational landscape of human diseases. Nowhere is the impact more apparent than in the field of cancer, specifically breast cancer. Understanding of the malignant process at a molecular level, coupled with the discovery of novel molecular techniques, has shifted the paradigm of treating breast cancer from a clinical, population-based risk assessment model to one based on molecular classification of disease.
Social communication intervention effects vary by dependent variable type in preschoolers with autism spectrum disorders

Individuals with autism spectrum disorders (ASDs) have difficulty communicating in ways that are primarily for initiating and maintaining social relatedness (i.e., social communication). We hypothesized that the way researchers measured social communication would affect whether treatment effects were found. Using a best evidence review method, we found that treatments were shown to improve social communication outcomes approximately 54% of the time. The probability that a treatment affected social communication varied greatly depending on whether social communication was directly targeted (63%) or not (39%). Finally, the probability that a treatment affected social communication also varied greatly depending on whether social communication as measured in (a) contexts very similar to treatment sessions (82%) or (b) contexts that differed from treatment on at least setting, materials, and communication partner (33%). This paper also provides several methodological contributions.
A Typology of Latin American Subcultures

O NE of the most perplexing problems in the study of complex national or regional cultures such as those of Latin America is the diversity of pattern and institution which they contain. There are a series of institutions, values, and modes of behavior which constitute throughout Latin America a "cultural common denominator" and which distinguish Latin American culture from other major culture spheres of the Western world (cf. Gillin 1947b and Wagley 1948). But the "common denominator" of modern Latin America does not consist simply of those institutions, values, and behavior patterns held in common by most of the Latin American population. Regular cultural differences within the complex and heterogeneous national societies must also be considered. A conceptual framework based on these differences is much needed to provide a context for the extant data and to guide future research. This is especially true with respect to the numerous anthropological community studies, whose contribution to our knowledge of a national culture is often lessened by an inadequate definition of just what variety of the national culture is being considered-or, in other words, what segment of the diverse population they treat. The purpose of the present article is to suggest a taxonomic system of subcultures which we hope will have operational utility throughout Latin America. This attempt to provide a classificatory system for ordering cultural data on Latin America is obviously not unique. As we shall discuss in more detail below, Redfield (1941), by implication at least, distinguished four types of communities for Yucatan, although only the folk and urban types were emphasized. Steward (1953) and his associates in the Puerto Rican project isolated a series of significant Puerto Rican subcultures for study.' And recently, there has been published a series of articles, dealing mainly with Latin America, aimed at refining and extending Redfield's folk-urban concepts. Most of these discussions of Redfield's classification and most attempts to develop a sociocultural taxonomic system have dealt with varieties of whole local communities treated as whole societies. This is to be expected from a discipline whose traditional research methods involved prolonged, sedentary, and intimate contact with a restricted locale and the analysis of local sociocultural wholes. But it is apparent that many of the communities studied in Latin America by anthropologists have an internal heterogeneity of culture pattern depending upon class differences, differences between rural and urban residents of the same community, and other factors, too numerous to list. It is therefore often
Seasonal patterns and vertical distributions of fine roots of alfalfa (Medicago sativa L.)

Abstract Seasonal patterns and vertical distributions of alfalfa root systems were investigated with field experiments and a simulation model. We carried out root excavations on an established alfalfa stand at Davis, California, in 1982 and 1983. Thirty-six soil cores to a depth of 150 cm were taken seven times in 1982 and seventy-two soil cores to 30 cm were taken nine times in 1983 over the growth seasons. Live fine roots were recovered through six (in 1982) or seven (in 1983) procedures, including detailed hand sorting for removing debris. Our studies revealed that fine root mass was generally greatest in spring and fall and least during summer. Secondary minima were found within each harvest cycle. At all samplings, root mass declined exponentially with depth. A simulation model was developed for studying dynamics of alfalfa fine roots. The model has two components: root growth and death. Actual growth rate of fine roots was determined by potential growth rate and dependent on soil temperature, water and carbohydrate supply. Root death was controlled by the maximum death rate and influenced by soil temperature and nonstructural carbohydrate in roots. Through differential changes in simulated growth and death rates, the model predicted well the temporal and vertical distributions of fine root mass. A high amount of fine root mass was maintained in spring by rapid growth and moderate death rates. Frequent harvests reduced root mass in summer. Root mass increased in fall again due to a prolonged high growth rate. Sensitivity analyses indicated vertical distributions varied strongly with carbohydrate supply and soil temperature.
Disaster evacuation behavior: Tourists and other transients: by Thomas E. Drabek Boulder, CO: Natural Hazards Research and Applications Information Center, 1996, 370 pages

(1998). Disaster evacuation behavior: Tourists and other transients. The Social Science Journal: Vol. 35, No. 3, pp. 465-467.
The Endosymbiont Arsenophonus Provides a General Benefit to Soybean Aphid (Hemiptera: Aphididae) Regardless of Host Plant Resistance (Rag)

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), invokes substantial chemical treatment and economic cost in North America. Resistant soybean genotypes hold promise as a low-impact control methodology, but soybean aphid "biotypes" capable of development on resistant soy cast doubt on the durability of soy resistance. We hypothesized that variation in soybean aphid ability to colonize resistant soy is partially attributable to a bacterial symbiont of soybean aphid, Arsenophonus. We used microinjection to manipulate Arsenophonus infection in both virulent and avirulent aphid biotypes, resulting in five pairs of infected versus uninfected isolines. These isolines were subjected to various population growth rate assays on resistant Rag versus susceptible soybean. We found that aphid virulence on Rag soybean was not dependent on Arsenophonus: virulent aphid biotypes performed well on Rag soybean, and avirulent aphid biotypes performed poorly on Rag soybean, regardless of whether Arsenophonus was present or not. However, we did find that Arsenophonus-infected clones on average performed significantly better than their paired uninfected isolines. This pattern was not consistently evident on every date for every clone, either in the population assays nor when we compared lifetime fecundity of individual aphids in a separate experiment. Nevertheless, this overall benefit for infected aphids may be sufficient to explain the high frequency of Arsenophonus infection in soybean aphids.
THE PSYCHOLOGICAL DISTANCE TO REWARD1

Pigeons' responses in the presence of two concurrently available (initial-link) stimuli produced entry into one of two different and mutually exclusive terminal link stimuli according to identical but independent variable-interval schedules. In one experiment, a two-component chained fixed-interval schedule produced food in one terminal link while a simple fixed-interval schedule produced food in the other terminal link. When the interreinforcement intervals were equal in the two terminal links (i.e., the simple fixed-interval was twice the size of each of the components in the chained schedule) pigeons preferred the simple fixed-interval as measured by their relative rates of responding in the concurrently available initial links. This preference increased as the duration of the terminal links increased. The preference could be reversed by making the simple fixed-interval schedule sufficiently longer than the chained schedule. In the second experiment, the terminal links consisted of two- vs three-component chained fixed-intervals, again with equal interreinforcement intervals. Pigeons preferred the two-component chain to the three-component chain, although these results were less consistent and less dramatic than those in the first experiment. Again, preference increased as the duration of the terminal links increased. The results show that an organism's choice for a schedule will be substantially lowered by the chaining operation even when the interreinforcement interval remains constant.
WE-A-301-07: Using Prior Images with Registration in Penalized Likelihood Estimation for CT with Sparse Data

Purpose: We aim to develop tomographic reconstruction methods that utilize prior CT volumes to improve image quality for sparse and undersampled datasets. The ability to handle such data has applications in region‐of‐interest scanning, tomosynthesis, and intraoperative imaging based on few view angles. While compressed sensing techniques like the PICCS algorithm are attractive, there are potential drawbacks. Such approaches often rely on pre‐registered prior images and the forward models for PICCS‐type algorithms tend to be simplified and ignore the noise model. We leverage the ability of likelihood‐based techniques to incorporate both prior images and sophisticated forward models. Methods: We have developed a framework for reconstruction of sparse tomographic data based on penalized‐likelihood estimation. The objective function for this approach is composed of a likelihood term that incorporates the forward model and noise; and a parameterized penalty term that discourages differences from the prior image. The penalty uses a compressed sensing norm and is parameterized to accommodate registration of the prior scan. An iterative algorithm is used to simultaneously solve for the tomographic volume and the registration parameters. The framework is general and can be used with both rigid and deformable registrations. Results: Reconstruction of sparse data using the proposed approach is demonstrated in cases where either rigid or deformable registration is employed in the reconstruction objective. We compare reconstruction results with traditional approaches where prior image data is not utilized. We find a substantial improvement in image quality with significant reduction in artifacts that are associated with the sparse data acquisitions. Conclusions: A new class of penalized‐likelihood estimator has been developed that simultaneously refines attenuation and registration estimates. The framework is general and supports both rigid and non‐rigid transformations of the prior imagery.Image quality and handling of artifacts using the proposed estimator with sparse data is superior to traditional approaches.
The rise in the total iron-binding capacity after iron overdose

Study objectives: To determine if and to what extent the total iron-binding capacity (TIBC) would increase following an iron overload, and to identify specific iron-binding proteins that might be responsible for the increased TIBC. Design: A prospective laboratory investigation. Setting: A certified regional poison control center. Participants: Six healthy adult male volunteers. Measurements and main results: All volunteers ingested 20 mg/kg of elemental iron. Blood samples were drawn at hourly intervals for eight hours and analyzed for serum iron, TIBC, transferrin, ferritin, lactoferrin, glucose, bicarbonate, and WBC. Within two hours of ingestion, subjects developed symptoms of toxicity, including nausea, lightheadedness, vomiting, severe crampy abdominal pain, and voluminous diarrhea. The TIBC was statistically significantly increased at all points measured from one to six hours. Despite rising above 300 μ g/dL in five of six subjects, the serum iron never exceeded the TIBC in any subject. Transferrin and ferritin did not increase to account for the increased TIBC. The lactoferrin levels did increase, but they did not correlate with significant increases in the TIBC. Conclusions: Twenty mg/kg of elemental iron caused clinical toxicity in this study, and after iron overload the colorimetric TIBC increased by unknown mechanisms.
How metaphysics is special: comments on Bennett

Karen Bennett argues that there is no distinct problem with metaphysics, and she proposes a disjunctive conception of the subject matter of metaphysics. This paper critically examines her arguments and positive view. I defend that metaphysics prima facie is distinctly problematic, and I raise some questions about Bennett’s disjunctive conception of the subject matter of metaphysics and the a priori aspect of its methodology.
Emerging role of bone morphogenetic proteins in adipogenesis and energy metabolism

Bone morphogenetic proteins (BMPs) regulate many processes in embryonic development as well as in the maintenance of normal tissue function later in adult life. However, the role of this family of proteins in formation of adipose tissue has been underappreciated in the field of developmental biology. With the growing epidemic of obesity, improved knowledge of adipocyte development and function is urgently needed. Recently, there have been significant advances in understanding the role of different members of the BMP superfamily in control of adipocyte differentiation and systemic energy homeostasis. This review summarizes recent progress in understanding how BMPs specify adipose cell fate in stem/progenitor cells and their potential role in energy metabolism. We propose that BMPs provide instructive signals for adipose cell fate determination and regulate adipocyte function. These findings have opened up exciting opportunities for developing new therapeutic approaches for the treatment of obesity and its many associated metabolic disorders.
Hippocampal epileptic activity induced by localized ventricular perfusion with high-potassium cerebrospinal fluid.

Abstract The effect of increasing K+ concentration in CSF on hippocampal neurons was studied by local perfusion of the inferior horn of the lateral ventricle of cats chronically prepared with implanted cannulae and electrodes. Localized paroxysmal discharge appeared from the perfused hippocampus after a latent period of 10–50 min when K+ in the perfusing CSF circulated at a rate of 0.81–1.62 μEq/min. The intensity of discharges was greater and the latent period shorter when K+ in CSF was increased from 8 mEq/liter to 16 mEq/liter. Single shocks delivered to dorsal hippocampus do not induce convulsive activity when K+ in CSF is normal, but induce convulsive activity when delivered during the “latent period” of a perfusion with high K+ CSF. The pattern of discharges suggested a primary action of K+ on basilar dendrites of hippocampal pyramidal cells. DC recording showed spike bursting superimposed on the repolarizing slope of a large negative slow wave indicating a possible disturbance of inhibitory phenomena.
Use of half-tetrad analysis to discriminate between two types of 2n egg formation in a potato haploid

The ratio of the first division restitution (FDR) to second division restitution (SDR) 2n eggs was estimated in 4182t, a haploid (2n = 2x = 24) of Solanum tuberosum L. that produces 2n eggs by the two modes. The segregation of three genes previously mapped relative to their centromeres, Pgm-2 (2.0 cM), Mdh-1 (33.5 cM), and 6-Pgdh-3 (30.1 cM) was analyzed in the tetraploid offspring of a 2x × 4x cross. Based on the segregation of the Pgm-2 locus, 39.7% of the progeny originated from FDR 2n eggs and 60.3% from SDR. Segregation patterns of the two distal loci within the FDR-derived 4x subpopulation indicated that the gene–centromere recombination rate during megasporogenesis was significantly reduced for Mdh-1 when compared with a previous estimate during microsporogenesis. In the SDR-derived 4x subpopulation, the gene–centromere recombination rates for Mdh-1 and 6-Pgdh-3 were not significantly different from previous estimates. Tetraploid progeny generated from one 2x × 4x cross where the 2x parent produces...
Policy Needs Regarding the Duty to Protect in Epidemiological Research with High-Risk Populations

The paper presents an analysis of policy directives needed to respond to threats of harm (e.g., violence against third parties) that may arise in the course of conducting descriptive epidemiological research with high-risk populations. It identifies two key areas where new policies must be developed to guide researchers conducting such investigations. The paper recommends that: (1) an NIH consensus panel be convened to set standards, analogous to Common Toxicity Criteria (CTC) criteria, to classify the severity of different types of indirect, non-research-related risk; and (2) case-based training modules be developed and incorporated into public health research ethics courses and training programs, to enhance researcher judgments in determining the likelihood of harm in different situations. In addition, researchers, Institutional Review Boards (IRBs) and community advisory groups must consider the issue of staff safety and the effectiveness of available responses to reduce the threat of harm. The author reviews and discusses implications for informed consent and IRB review.
Feelings and the body: The Jamesian perspective on autonomic specificity of emotion §

‘‘What is an emotion?’’ William James’s seminal paper in Mind (1884) proposed the idea that physiological and behavioral responses precede subjective experience in emotions that are marked by ‘‘distinct bodily expression.’’ This notion has broadly inspired the investigation of emotion-specific autonomic nervous system activity, a research topic with great longevity. The trajectory of this literature is traced through its major theoretical challenges from the Cannon–Bard, activation, and Schachter– Singer theories, through its rich empirical history in the field of psychophysiology. Although these studies are marked by various findings, the overall trend of the research supports the notion of autonomic specificity for basic emotions. The construct of autonomic specificity continues to influence a number of core theoretical issues in affective science, such as the existence of basic or ‘natural kinds’ of emotion, the structure of affective space, the cognition–emotion relationship, and the function of emotion. Moreover, James’s classic paper, which stimulated the emergence of psychology from philosophy and physiology in the latter nineteenth century, remains a dynamic force in contemporary emotion research.