cssi/SciSciGPT-SciSciNet huggingface dataset:
Summer Feeding of Dairy Cattle. A Review

Summary Income for dairy farmers during the summer depends to a considerable extent on more pasture herbage production in hot-dry weather. The results of recent studies indicate that dairy cattle fed an adequate ration, and allowed to graze nights and days with shade during the days, are far less affected by high environmental temperatures than previously supposed. Increased quality and quantity of forage may be enhanced by: (a) growing crops more resistant to heat and drought, (b) maintaining more moisture in the soil by less defoliation of plants which give shade to the soil, (c) irrigation, and (d) fertilization of the soil (especially with nitrogen, phosphorus, and potassium). The problems involved in using animal production (growth, milk yields) in pasture evaluation were pointed out. Indirect methods of pasture evaluation using internal and external indicators were described. A combination of internal and external indicators makes possible the estimation not only of the chemical composition but also of the coefficient of digestibility and dry matter intake of pasture. Dry matter intake from pasture is variable, but usually is about 30 to 35lb. per day for cows weighing 1,200lb. Grazed pasture herbage is higher in crude protein and lower in crude fiber and higher in digestibility than comparable hand-fed herbage. The requirements of grazing cattle are about the same as in barn-feeding, with the exception of digestible energy. Grazing cattle require from 1 to 3lb. of TDN per cow per day more than those barn-feeding. Losses of pasture herbage from trampling, when properly managed, are about 10 to 15%. These losses are much higher with tall pastures. Temporary pastures, such as Sudan grass, are needed in many areas to supplement perennial pastures during the summer. The success of different systems of pasture utilization hinges on proper management (proper stocking rate, use of high-producing cows). Rotational and strip-grassing systems aid in using intensive pastures. Soilage may be used to advantage on farms where good pasture land is not conveniently located. Where soilage and stored feed may be used to advantage was pointed out. The fermentation vat of calves fed feeds other than milk alone is sufficiently developed at 2 to 4 mo. of age to handle good pasture, but the calves will starve on poor pasture. Certain pasture forages, such as Sudan grass, may contain considerable hydrocyanic acid. When properly managed, however, the danger from prussic acid poisoning is not great. Although the cause of pasture bloat is not known, recent results indicate that the administration of penicillin prevents bloat for a short time. Also, vegetable oils sprayed on "bloaty" pastures, added to the drinking water or to the feed, reduce the incidence of bloat. Milk produced by cows on pasture is more resistant to oxidized flavor than when winter feeds are fed. Pasture feed flavors may be avoided by removing cows from pasture 3 to 5hr. prior to milking.
901-75 Early Improvement in Congestive Heart Failure Following Correction of Secondary Mitral Regurgitation in End-Stage Cardiomyopathy

Mitral regurgitation (MR) frequently complicates cardiomyopathy (CM) and contributes to symptoms of congestive heart failure (CHF). This study was undertaken to assess the changes in CHF and left ventricular (LV) systolic performance following mitral valve reconstruction (MVR) in patients with severe MR secondary to end-stage dilated CM. Nine consecutive patients (age 64 ± 10 yrs) with severe LV dysfunction (ejection fraction [EF] 18 ± 5% [10–25%]). severe MR and NYHA Class III (n = 1) or IV (n = 8) CHF despite aggressive medical therapy underwent MVR. All patients were receiving therapy including digoxin, diuretics and afterload reducers. Two patients were awaiting heart transplantation. There were no operative deaths or deaths on 17 ± 5 (8-24) week follow-up (PostOp). All patients noted symptomatic improvement NYHA Class improved from 3.9 ± 0.3 pre-operatively (PreOp) to 1.7 ± 0.5 (p l 0.001) Diuretic requirements were markedly lower for 5 of 9 patients and stable for the remaining 4. Ouantitative 2D echo/Doppler was performed on all patients PreOp and on 8 of 9 patients PostOp. MR was absent or mild on follow-up in all. Matched PreOp and PostOp LV end-diastolic volume (EDV), EF, forward cardiac output (CO) and regurgitant fraction (RF) were compared for change (Δ): EDV(cc) EF(%) CO(L/min) RF(%) PreOp 317 ± 111 18 ± 5 3.1 ± 1.0 70 ± 12 PestOp 291 ± 106 24 ± 9 4.6 ± 0.8 13 ± 10 Δ -26 ± 31 +6 ± 5 +15 ± 0.9 -57 ± 15 P 0.04 0.02 0004 l0.001 Improvement in CHF occurred after MVR in all patients on short-term follow-up, accompanied by lower LV end-diastolic volume and increased EF and forward cardiac output Mitral reconstruction may be a new strategy for the treatment of patients with severe MR complicating end-stage cardiomyopathy.
Maternal Expectancies for Achievement, IQ, and Autonomous Achievement Motivation in Kindergarten Children:

This study examined the relationship between maternal expectancies of achievement and autonomous achievement motivation in children as moderated by IQ. Subjects were 67 white kindergartners and the...
Getting individual differences in autonomic reactivity to work for instead of against you: determining the dominant "psychological" stress channel on the basis of a "biological" stress test.

The purpose of this study was to develop a procedure to increase the re liability of autonomic measures, such as skin conductance (SC) and heart rate (HR), when assessing negative emotional responding. The strategy was to capitalize on the individual difference factor by determining prior to the start of an experiment each subject's most reactive autonomic channel. To achieve this objective, a “biological” stress test (balloon-burst test) was used. Subjects were then classified by using a median-split, rank-ordered procedure, as high SC responders, high HR responders. high responders in both channels, or low responders in both channels. The generality of the responder-non-responder classification was then assessed to a “psychological” stressor which involved presentations of a fear-eliciting bodily-injury slide. Transfer effects were obtained with those subjects defined as high responders on a given channel displaying greater reactivity on that channel when compared to subjects classified as low responders. The implications of these findings for clinical research were discussed.
The multistep theory of aging: relation to the forbidden-clone theory. A theoretical article

Abstract The multistep theory of aging is presented in a revised form. The pathogenesis of disease is represented by multistep processes consisting of sequences of steps linking states that are organized in serial chains. Cells or other disease-related entities make irreversible transitions from one state in a chain to the next. The clinical manifestations of a given disease commerce when a sufficient number of cells has populated the final state of each member of a set of multistep processes. The mean number of cells in the final state of each process is calculated with the use of Laplace transform techniques. The result is a sum of decaying exponential functions of time which approaches the power function obtained by previous investigators if the probability of transition between states is small. Poisson statistics are used to calculate the probability of onset of disease as a function of the mean numbers of cells in the final states of the multistep processes. Under certain conditions, the multistep theory yields the same expression as the forbidden-clone theory for the incidence of disease as a function of age. Thus age-specific disease-prevalence data which has been advanced to support the forbidden-clone theory is equally supportive of the multistep theory.
Instability of the "steady state" during exercise.

The “steady state” of exercise is only relatively steady; considerable fluctuation in the rate of oxygen consumption occurs from minute to minute. The standard deviations expressed in per cent of mean O2 consumption are smallest with a moderate work load which requires a certain effort and concentration of the subject; they are greater at either extreme of work load. The instability of the “steady state” of exercise appears to be a normal phenomenon.
Fundamental processes in the incineration of chloroaromatic compounds

Abstract This paper deals with the use of fundamental chemical kinetic information to gain insight into some aspects of the incineration of dilute concentrations of chloroaromatic compounds. The focus is on the elementary single step reactions that these and other organic constituents in waste mixtures undergo during incineration. The relationship between rate constants for the relevant elementary reactions and the destruction efficiency as defined in current regulations is described. Attention is focused on the importance of OH radicals and H-atoms as agents for effecting the high temperature destruction of organic compounds. The available data on these processes are reviewed and it is suggested that the rate constants for hydrogen atom reactions may play an important role in correlating the observed distribution of organic effluents from incineration. Recent measurements on rate constants of hydrogen atom attack on aromatics are described. These data are used in computer simulations that lead to the description of the temporal behavior of chloroaromatics during the pyrolytic decomposition of compounds containing reactive groups which may be found in the gas phase during municipal waste incineration.
Alternative Views of the Psychiatrist's Role

Two views of the inpatient psychiatrist's role are examined using data from a study of discharges from a mental hospital. One view of the psychiatrist sees him in the traditional professional role using his skills to advise and direct patients. Another view of the psychiatrist pictures him rationalizing and legitimizing in medical-psychiatric terms actions taken toward patients, such as discharges, which occur neither for professionally acknowledged medical nor psychiatric reasons. The desires regarding discharge timing held by the patient and a member of his family are found strongly and positively related to the actual timing of release. These desires account for almost all of the relationship between the psychiatrist's medical-psychiatric evaluation of the patient and the timing of discharge, suggesting, along with other supporting data, that the psychiatrist's professional judgments are at best indirect determinants of the discharge decision. Observations of psychiatrist-patient relationships over time also suggest that psychiatrists sometimes alter their evaluations of a patient's psychiatric condition in response to pressures from the family and patient, allowing professional prescription of discharge or retention as the family or patient demands. Implications of these findings are briefly explored.
The reliability of power distribution systems as calculated using system theoretic concepts

Reliability of distribution systems is an important issue in power engineering for both utilities and customers. Power distribution reliability is closely related to individual component reliability. In this paper, the reliability as measured by certain count indices, mainly the System Average Interruption Duration Index (SAIDI) and the System Average Interruption Frequency Index (SAIFI), is quantified in terms of individual distribution component reliability. This is an extension of previously reported results. The value of the approach lies in distribution expansion planning in which a radial system may be networked with a view to improve reliability. The effect of inserting Distributed Generation (DG) in the distribution system is studied in this paper. The result of this insertion may be that the number of outages increases because of the possible failure of the DG hardware. Two new indices for this application are proposed: the ratio of DG energy to interrupted energy and the ratio of DG operating duration to outage duration.
On the exact solution of the Parity- N problem using ordered neural networks

Abstract In this paper, an exact solution of the Parity-N function representation problem is provided using a fully connected feedforward (ordered) neural network. The solution requires neither training nor adaptation, and employs (N−1) neurons. It is shown that any function σ: R → R with the property: σ(−1)=σ(1)=1 and σ(0)=0, can be used as the neural network activation function.
Communication processes and consumerism: The case of Venezuela

This study investigates the influence of various television content types on different dimensions of consumerism. We hypothesize that exposure to different content on television (entertainment programming, telenovelas, and news) influences ideas on consumerism differentially. Interpersonal discussion of societal issues is assumed to have a positive impact on consumerism. Finally, we predict that several indicators of location within the social structure affect both communication processes and consumerism conceptions. Survey data were collected in a large metropolitan area of a media‐rich, underdeveloped society. Using structural equation modeling with latent variables, the proposed model provided a good fit There is at least partial support for most of the hypotheses. We conclude that communication processes have predictable effects on what individuals perceive to constitute a good life in both abstract and concrete terms, and that this may have implications for pursuing development plans.
Ultraviolet-absorbing compounds in the mucus of temperate Pacific tidepool sculpins: variation over local and geographic scales

Temperate tidepool fishes of the family Cottidae (Teleostei) display biogeographic dis- tribution patterns that vary with latitude and elevation within the intertidal zone. Middle and high intertidal pool species show a pattern of 'species replacement', with southern species being replaced by northern species at discrete locations along the coast. Lower intertidal pools, on the other hand, are dominated by a single species, Oligocottus snyderi, that occurs over an extremely wide latitudi- nal range. As a consequence of both latitudinal and elevational patterns, these fish experience vari- able amounts of ultraviolet (UV, 280 to 400 nm) irradiation both between and within species. The mucus of tidepool sculpins was analyzed by absorbance spectrophotometry to compare concentra- tions of UV-absorbing compounds in the mucus of fish, with regard to geographic location or inter- tidal microhabitat. Mucus from northerly fishes absorbed significantly less UV than the mucus of southerly fishes. Overall, mucus from high intertidal pool fishes absorbed significantly more UV than mucus from middle or lower intertidal pool fishes, but differences were not detectable within a site. The mucus spectra of all fish surveyed contained a single UV absorption peak with maximum absorbance (λmax) in the short-wavelength UVA (UVA = 320 to 400 nm, λmax range = 323 to 331 nm). Compounds with λmax in the UVB (280 to 320 nm) or longer-wavelength UVA (ca. 360 nm) were not found, although these compounds were present in 38 (UVB) and 59% (longer UVA) of tropical species' mucus (138 species surveyed).
Implicit Costs of Empire: Bureaucratic Corruption in Nineteenth-Century Cuba

Cycles of bureaucratic corruption in nineteenth-century Cuba evolved according to institutional conditions shaped by interest groups, financial needs, imperatives of colonial governance, and internal conflicts and war. Corrupt gain inimical to general public interest was not a consequence of cultural constants, but of unreconstructed institutional flaws and weaknesses. The risks of engaging in bureaucratic corruption diminished under the systematic condoning of administrative faults, collusive allowance of illegal slave trafficking, and a code of illegal rewards expected by loyalist officials opposing colonial reform. Despite some few anti-corruption initiatives, the prosecution and punishment of corrupt officials was lax. The implicit, yet significant, financial, institutional and political costs of corruption contributed to the demise of Spanish imperial dominion over Cuba and left a damaging burden and legacy for Cuban civil society.
Serum transaminase levels in boys with Duchenne and Becker muscular dystrophy.

OBJECTIVE: Serum alanine transaminase (ALT) and aspartate transaminase (AST) levels are commonly used as biochemical indicators of hepatocellular injury but can also detect occult muscle disease. High concomitant serum creatine phosphokinase (CPK) levels can point to muscle as the source of high transaminase levels. Nevertheless, clinicians may be reluctant to attribute high transaminase levels to muscle. METHODS: Study patients were boys with a genetic or biopsy-confirmed dystrophinopathy whose concomitant serum CPK, ALT, and AST levels were measured. RESULTS: We report 82 enzyme data sets from 46 patients with Duchenne muscular dystrophy (DMD) and 9 with Becker muscular dystrophy. Our results show a linear relationship between serum CPK and serum ALT and AST and a logarithmic relationship between serum enzyme levels and age for boys with DMD. We developed a mathematical model to predict serum ALT and AST levels when the serum CPK level and age are known. For 6 boys, initial failure to consider muscle as a cause of high transaminase levels led to delay of diagnosis and extensive testing for hepatic dysfunction. A second group of 4 boys with known DMD were investigated for liver disease after high transaminase levels were detected. Serum transaminase levels were highest in ambulant boys with DMD, whose levels reached 1220 U/L (ALT) (22.6 times higher than upper-limit normal levels) and 801 U/L (AST) (12.3 times higher than upper-limit normal levels). CONCLUSIONS: By recognizing muscle as a potential source of serum transaminase levels, clinicians can avoid unnecessary and invasive procedures, expedite clinical diagnosis, and avoid unnecessary cessation of concomitant drug therapy.
The quantitative estimation of ergotamine and ergotoxine by paper chromatography

Under specified conditions the R 1 f values of ergotamine and ergotoxine were found to increase in proportion to the quantity spotted on a paper chromatographic strip. This change in R 1 f value is used as a means of quantitative estimation of these alkaloids.
Exploiting the avian immunoglobulin system to simplify the generation of recombinant antibodies to allergenic proteins.

Summary Background Monoclonal antibodies are a valuable tool in the study of allergens, but the technology used in their generation can be slow and labour-intensive. Therefore, we have examined recombinant antibody development by phage-display against single allergens and protein mixtures. Objective We used the avian immunoglobulin system (generated from single VH and VL genes) to provide a rapid method for generating highly specific recombinant antibody fragments from a minimal number of animals. Methods A single-chain antibody fragment (scFv) library was generated from a single chicken immunized with model allergens. ScFvs were isolated by phage-display and their properties investigated by ELISA and Western blot. Results Mono-specific scFvs were generated against recombinant Fel d 1 and native Amb a 1. Pannings against yellow jacket venom extracts only yielded clones that reacted with multiple proteins in the venom extract. The scFvs from each panning type were effectively expressed in Escherichia coli and readily purified. Highly specific and sensitive recognition of Fel d 1 and Amb a 1 was demonstrated in ELISA, with scFvs displaying antibody-concentration-dependent absorbance curves down to picogram levels of antibody. The specificity of selected antibodies for their cognate antigen was further confirmed in Western blot analysis, with scFvs directed to either Fel d 1 or Amb a 1 showing no reactivity for the other antigens used in immunization. Anti-Amb a 1 scFvs also mapped Amb a 1-isoform location in Western blot of ragweed extracts separated by 2D SDS-PAGE. DNA sequence analysis of scFvs showed that multiple different clones had been generated against Fel d 1 and Amb a 1. Using two anti-Fel d 1 scFv for ELISA analysis of Fel d 1 content in crude cat pelt extracts, we could produce data which were highly similar (P=0.33 and 0.89 by paired t-test analysis) to those obtained using conventional assays (radial immunodiffusion). Conclusion Phage-display technology may generate multiple allergen-specific recombinant antibody fragments from a single chicken, to allergens from mammalian, plant and insect sources. The resulting antibody fragments are of demonstrable use in allergen identification and quantification, in comparison with standard immunoassays.
Case Study: MR Treatment for Calcific Tendinitis:

Therapies for calcific tendinitis are often invasive. This report describes a case of calcific tendinitis treated with noninvasive magnetic resonance (MR) therapy. Ten-minute MR treatments were adm...
Biomass production for bioenergy using recycled wastewater in a natural waste treatment system

Abstract Bioenergy production from biomass is proposed as a method to solve part of the nation's energy problem. However, biomass and bioenergy production is questioned as an environment-friendly approach due to the potential increase of water pollution and the potential decrease of available water resource. A conceptual model of an integrated natural waste treatment system that produces biogas and biomass for bioenergy, treat waste and wastewater, conserve fresh water, and decrease the potential water pollution is presented. The potential biomass production from water hyacinth, duckweed, cattail, and knotgrass was investigated using recycling wastewater from an integrated natural waste treatment system from 2005 to 2008. Although the biomass production from recycling wastewater was not controlled for maximum production, this research identified the large potential impact that could be made if these systems were implemented. The overall average water hyacinth growth rate was high to 0.297 kg wet wt./m 2 /day during a research period of over 500 days, including both the active and non-active growing seasons. The average daily growth rates of duckweed, cattail, and knotgrass were 0.099–0.127, 0.015, and 0.018 kg wet wt./m 2 , respectively. This research illustrated that water hyacinth was a more promising aquatic plant biomass for bioenergy production when wastewater effluent was recycled as water and nutrient sources from an integrated natural waste treatment system.
The Issue of Standing in Cost‐Benefit Analysis

Insufficient attention has been given in cost-benefit analysis to whose benefits are to be counted. Foreigners, illegal aliens, fetuses, and criminals are problematic cases. Persons or entities may be given “standing” by participation in decision processes; by having their preferences counted, if meaningful preferences exist; by having their welfare counted, if they cannot express their preferences; or by representation by others whom they do not choose. Problems of standing arise in the valuation of life, the consideration of future generations and nonhuman entities, and equity weighting. These problem may be treated by altering the scope of the expert community or by interaction between that community and the political community. They are not always resolvable, but should be treated more explicitly.
On the Theory of Electron Multiplication in Crystals

The theory of the multiplication of electrons in strong electrostatic fields is investigated. It is found that the non-polar coupling between electrons and lattice has an important effect on the retardation of electrons in polar materials as well as in non-polar ones if the electron is to be accelerated to an energy at which it may ionize the bulk material. The retardation arising from this coupling is a maximum when the energy of the electron corresponds to a value near the boundary of the Brillouin zone, in contrast with the retardation arising from purely polar interaction in polar crystals which has its maximum when the energy is near the energy of the polar modes. The existence of the non-polar interaction seems to make the difference between the breakdown criteria of von Hippel and Fr\"ohlich of less practical importance than was supposed hitherto. It is found that statistical fluctuations in the velocity of the electrons plays a very important role in determining electron multiplication and that the field required to produce breakdown in a standard specimen actually is no more than twenty percent of the value obtained from the criteria of von Hippel and Fr\"ohlich.
APEX: automated policy enforcement eXchange

The changing nature of document workflows, document privacy and document security merit a new approach to the enforcement of policy. We propose the use of automated means for enforcing policy, which provides advantages for compliance and auditing, adaptability to changes in policy, and compatibility with a cloud-based exchange. We describe the Automated Policy Enforcement eXchange (APEX) software system, which consists of: (1) a policy editor, (2) a policy server, (3) a local daemon on every PC/laptop to maintain local secure up-to-date storage and policy, and (4) local (policy-enforcing) wrappers to capture document-handling user actions such as document export, e-mail, print, edit and save. During the performance of relevant incremental change, or other user-elicited action, on a composite document, the document and its metadata are scanned for salient policy eliciting terms (PETs). The document is then partitioned based on relevant policies and the security policy for each part is determined. If the document contains no PETs, then the user-initiated actions are allowed; otherwise, alternative actions are suggested, including: (a) encryption, (b) redirecting to a secure printer and requiring authorization (e.g. PIN) for printing, and (c) disallowing printing until specific sensitive data is removed.
Cerebral white matter changes in acquired immunodeficiency syndrome dementia: Alterations of the blood‐brain barrier

The cause of acquired immunodeficiency syndrome (AIDS) dementia, which is a frequent late manifestation of human immunodeficiency virus (HIV) infection, is unknown but radiological and pathological studies have implicated alterations in subcortical white matter. To investigate the pathological basis of these white matter abnormalities, we performed an immunocytochemical and histological analysis of subcortical white matter from AIDS patients with and without dementia, from pre-AIDS patients (asymptomatic HIV-seropositive patients), and from HIV-seronegative control subjects. Reduced intensity of Luxol fast blue staining, designated "diffuse myelin pallor," was detected in 8 of 15 AIDS dementia patients, 3 of 13 AIDS nondemented patients, and none of the pre-AIDS patients (n = 2) or control subjects (n = 9). In contrast to Luxol fast blue staining, sections stained immunocytochemically for myelin proteins did not show decreased staining intensities in regions of diffuse myelin pallor. In addition, neither demyelinated axons nor active demyelination were detected in light and electron micrographs of subcortical white matter from brains of patients with AIDS dementia. An increase in the number of perivascular macrophages and hypertrophy of astrocytes and microglia occurred in brain sections from HIV-infected patients. These changes were not specific to dementia or regions of diffuse myelin pallor and they occurred in both gray and white matter. In contrast to the lack of myelin pathology in AIDS dementia brains, significant accumulations of serum proteins in white matter glia were detected in the brains of 12 of 12 patients with AIDS dementia and 6 of 12 AIDS patients without dementia. Serum protein-immunopositive cortical neurons were detected in the frontal cortex of 11 of 12 patients with AIDS dementia and 3 of 12 nondemented AIDS patients. Seronegative control subjects showed minimal serum protein immunoreactivity in both cortex and white matter. We conclude therefore that alterations in the blood-brain barrier and not demyelination contribute to the development of AIDS dementia.
Mechanisms of mutual functional interactions between HNF-4α and HNF-1α revealed by mutations that cause maturity onset diabetes of the young

Hepatic nuclear factor (HNF)-4α and HNF-1α are key endodermal transcriptional regulators that physically and functionally interact. HNF-4α and HNF-1α cooperatively activate genes with binding sites...
Where Do I Begin?: Designing Online Learning Courses Which Work

One of the greatest needs of faculty in adult and higher education today is to understand how to design distance learning courses which address the needs of their current and prospective students while upholding academic excellence and remaining feasible to develop (Simonson, Smaldino, Albright, & Zvacek, 2009; Palloff & Pratt, 2004). This article provides an overview of the rapidly changing field of distance learning with a focus on trends and lessons for faculty course design and facilitation. Beginning with distance learning, the article illustrates not only the possibilities for teaching and learning through a variety of inexpensive, popular and easy technologies, but will also leads into how to plan, design and facilitate courses which incorporate them. The basis for this model is 13 years of distance learning research, design and teaching, as well as extensive continued literature reviews. The aim is to assist faculty in identifying how to envision, plan, design and facilitate online classes which will best address the many demands they have to satisfy.
Evaluating Administrative Guidance and Cartels in Japan (1957-1988)

Abstract This paper uses cross-sectional and pooled time series data to examine the impact of administrative guidance and cartels in Japan. In general, government-organized cartels appear to have caused only small changes in prices and had no impact on sectoral margins. The lack of a stronger relationship between cartels and margins probably reflects either the difficulty of organizing cartels or the tendency of cartelized firms to compete away rents through competition through quality. It is also possible that Japanese cartels had little impact on prices because efforts to reduce costs offset incentives to raise prices. J. Japan. Int. Econ., March 1995, 9(1), pp. 000-000. Department of Economics, Harvard University, Cambridge, Massachusetts 02138.
Comparison of human and Hotelling observer performance for a fan-beam CT signal detection task.

Purpose: A human observer study was performed for a signal detection task for the case of fan-beam x-ray computed tomography. Hotelling observer (HO) performance was calculated for the same detection task without the use of efficient channels. By considering the full image covariance produced by the filtered backprojection (FBP) algorithm and avoiding the use of channels in the computation of HO performance, the authors establish an absolute upper bound on signal detectability. Therefore, this study serves as a baseline for relating human and ideal observer performance in the case of fan-beam CT. Methods: Eight human observers participated in a two-alternative forced choice experiment where the signal of interest was a small simulated ellipsoid in the presence of independent, identically distributed Gaussian detector noise. Theoretical performance of the HO, which is equivalent to the ideal observer in this case (see Sec. 13.2.12 inBarrett and Myers [Foundations of Image Science (Wiley, Hoboken, NJ, Year: 2004)], was also computed and compared to the performance of the human observers. In addition to a reference FBP implementation, two FBP implementations with inherent loss of HO signal detectability (e.g., by apodizing the ramp filter) were also investigated. Each of these latter two implementations takes the form of a discrete-to-discrete linear operator (i.e., a matrix), which has a nontrivial null-space resulting in the loss of detectability. Results: Estimated observer detectability index ( d A ) values for the human observers and SNR values for the HO were obtained. While Hanning filtering in the FBP implementation with a cutoff frequency of 1/4 of the Nyquist frequency reduces HO SNR (due to the reconstruction matrix's nontrivial null-space), this filtering was shown to consistently improve human observer performance. By contrast, increasing the image pixel size was seen to have a comparable effect on both the HO and the human observers, degrading performance. Conclusions: These results, which characterize HO and human observer performance for a signal detection task in fan-beam FBP noise, form a basis for applying model observer metrics to fan-beam CT when knowledge of the full image-domain noise statistics is important. Further, by calculating HO performance without relying on channels, these results are particularly relevant when an information theoretic approach is considered, e.g., in optimization of the image reconstruction algorithm with respect to preservation of signal detectability. Finally, the HO (which is here equivalent to the ideal observer) provides an absolute upper bound on detection performance, and our results therefore provide insight into the performance of human observers relative to the optimum for two different cases wherein ideal observer performance is compromised through degradation of the data quality. In one case (regularization), human performance is improved to practically ideal performance, and in the other (larger pixel size), ideal and human observer performance are approximately degraded equivalently.
A Landauer Approach to Nanoscale MOSFETs

A tutorial introduction to the theory of the nanoscale MOSFET is presented. The essential physics is first reviewed by examining numerical simulations. Next, the analytical theory of the ballistic MOSFET is introduced by presenting a simple derivation based on Boltzmann statistics. The extension to Fermi-Dirac statistics is then discussed. To clarify the connection to well-known results from mesoscopic transport, the TL = 0 K theory is then developed. Finally, qualitative arguments are used to discuss the role of scattering in nano-scale MOSFETs, and the relation of scattering theory to conventional MOSFET theory is examined.
The clinical and economic consequences of nosocomial central venous catheter-related infection: are antimicrobial catheters useful?

Central venous catheters (CVCs) are essential for many hospitalized patients, but they are associated with important infectious complications. Recent studies have indicated that CVCs coated with antimicrobial agents reduce the incidence of catheter-related bloodstream infection (CR BSI). To estimate the clinical and economic consequences of short-term central venous catheter-related infection and the potential usefulness of antimicrobial-coated catheters, we reviewed and synthesized the available relevant literature. Statistical pooling was used to estimate the incidence of both catheter colonization and CR BSI. The attributable mortality of CR BSI was also evaluated. In addition, the economic consequences of both local and systemic catheter-related infection was estimated from literature reports that used micro-costing and other techniques. Among patients in whom standard, noncoated CVCs are in place for an average of 8 days, 24.7% are expected to develop catheter colonization (95% confidence interval [CI 95 ], 22.0%-27.5%). Approximately 5.2% (CI 95 , 3.9%-6.5%) will develop CR BSI. The attributable mortality of CR BSI remains unclear, but recent studies are consistent with a range from 4% to 20%. An episode of local catheter-related infection leads to an additional cost of approximately $400, whereas the additional cost of CR BSI ranges from approximately $6,005 to $9,738. Formal economic analyses indicate that CVCs coated with antibacterial agents (such as chlorhexidine-silver sulfadiazine or minocycline-rifampin) likely reduce infectious complications, yielding economic advantages. In light of the substantial clinical and economic burden of catheter-related infection, hospital personnel should adopt proven cost-effective methods to reduce this common and important nosocomial complication.
Longitudinal endolymph movements induced by perilymphatic injections.

Abstract Endolymph movements and endocochlear potential (EP) changes were measured during disturbances of perilymphatic pressure, induced by injecting artificial perilymph into scala tympani (ST) or scala vestibuli (SV) of the guinea pig cochlea. Injections were performed either with or without an outlet made in the opposite perilymphatic scala. Injections into ST without an outlet induced large pressure changes but virtually no endolymph movement or EP change. Injection at the same rate into ST with an outlet in SV produced smaller pressure changes which were accompanied by a basally-directed displacement of endolymph and significant EP changes. The magnitude of endolymph displacements and EP changes varied as a function of injection rate. Injections into SV, either with or without an outlet in ST, produced apically-directed endolymph displacement and EP changes. For the SV injections without an outlet, the cochlear aqueduct and round window are likely to provide an outlet and compliance, permitting flow along the perilymphatic scalae to occur even when no ST outlet was provided. We conclude that endolymph movements are not dependent on the absolute pressure of the perilymph, but instead occur when small, sustained pressure gradients are present across the cochlear partition, corresponding to times when perilymph flow is induced. This study demonstrates that in the normal, sealed cochlea, endolymph and EP are insensitive to fluid injections into ST, but are sensitive to fluid injections into SV. Endolymph movements are therefore unlikely to be generated by cerebrospinal fluid pressure fluctuations (such as those produced by respiration, posture changes, coughing, sneezing, etc) which are transmitted to ST by the cochlear aqueduct.
Pulsed laser deposition of epitaxial AlN, GaN, and InN thin films on sapphire(0001)

Abstract Epitaxial aluminum nitride (AlN), gallium nitride (GaN), and indium nitride (InN) films were grown by pulsed laser deposition on sapphire(0001) substrates in high vacuum and in a nitrogen ambient of a few mTorr. The films were analyzed using X-ray diffraction, scanning electron microscopy, atomic force microscopy, and room temperature van der Pauw-Hall measurements. The AlN films were single crystalline with AlN(0001)‖sapphire(0001) and AlN[1100]‖sapphire[1120]. The GaN films were also single crystalline with the same orientation as the AlN films. The InN films were found to have a preferred crystalline orientation with InN(0001)‖sapphire(0001) and InN[1100]‖sapphire[1010]. The AlN films were insulating. The GaN film grown in high vacuum had an n-type carrier concentration of 1 × 10 18 cm −3 and a mobility of 300 cm 2 /V · s. The GaN film grown in 10 mTorr of N 2 had a p-type carrier concentration of 7.5 × 10 18 cm −3 and a mobility of 150 cm 2 /V · s. The InN films grown in high vacuum and 5 mTorr of N 2 were both p-type with carrier concentrations of 6.5 × 10 20 and 4.7 × 10 19 cm −3 , and mobilities of 30 and 240 cm 2 /V · s, respectively.
Piezoelectric contrast materials for ultrasound imaging

Piezoelectric ceramics and polymers can be used as a type of marker and contrast material for medical ultrasound imaging systems. High-frequency electrical signals are detected from surface electrodes when these materials are introduced into conducting media such as tissue and scanned by ultrasound imaging systems. Detected signals are applied to the imaging circuits of a modified ultrasound system such that they display a unique type of electrical image that shows the piezomaterial's polarization, shape, and position at arbitrarily high contrast compared to the conventional ultrasound acoustic image. The resulting piezoelectric image can be merged in real-time with conventional ultrasound acoustic imaging to form a composite image. This approach is of interest in the development of improved techniques for imaging medical devices that are implanted or otherwise introduced into the body.
Cardiac arrest following use of sumatriptan

I report a 35-year-old woman with occult coronary artery disease who experienced cardiac arrest within minutes after receiving a first-time dose of subcutaneous sumatriptan for migraine. The patient was resuscitated, and subsequent serial cardiac enzymes indicated myocardial infarction. Because sumatriptan can cause coronary artery vasospasm, patients with significant risk factors for coronary artery disease should be carefully evaluated for cardiovascular disease prior to the use of sumatriptan.
Doubly differential cross sections for the proton-impact double ionization of helium

A time-dependent close-coupling approach is used to investigate 6 MeV proton-impact double ionization of helium. We extract doubly differential (in the emission angles of both outgoing electrons) cross sections for comparison with recent experimental measurements. Good qualitative agreement is found between our calculations and the measurements. We also present differential cross sections for cases where the energy available to the outgoing electrons is unrestricted, which allows further information about the double escape process to be inferred.
Acid-base disorders.

1. Mara Nitu, MD* 2. Greg Montgomery, MD† 3. Howard Eigen, MD§ 1. *Associate Professor of Clinical Pediatrics, Section of Pediatric Pulmonology, Critical Care and Allergy; Medical Director, PICU/Riley Hospital for Children; Medical Co-Director of Lifeline Transport Team, Indianapolis, IN. 2. †Assistant Professor of Clinical Pediatrics, Section of Pulmonology, Critical Care and Allergy; Medical Director, Pediatric Bronchoscopy Laboratory, James Whitcomb Riley Hospital for Children, Indianapolis, IN. 3. §Billie Lou Wood Professor of Pediatrics, Associate Chairman for Clinical Affairs; Director, Section of Pediatric Pulmonology, Critical Care and Allergy, James Whitcomb Riley Hospital for Children, Indianapolis, IN. After completing this article, readers should be able to: 1. Understand the mechanisms for regulating acid-base physiology. 2. Know the differential diagnosis of metabolic acidosis associated with high anion gap and plan for initial management. 3. Know the differential diagnosis of normal anion gap metabolic acidosis. 4. Describe pulmonary compensatory changes in metabolic acidosis and alkalosis. 5. Understand how various diuretics can lead to acid-base imbalance. 6. Describe renal compensatory changes in respiratory acidosis and alkalosis. A 16-year-old girl who has no significant previous medical history presents to the emergency department with a 4-day history of nausea, vomiting, fever, chills, diarrhea, leg cramps, abdominal pain, and headaches. She is finishing her menstrual period and arrives with a tampon in place, which she reports that she inserted yesterday. Her vital signs include a heart rate of 165 beats/min, respiratory rate of 28 breaths/min, blood pressure 65/30 mm Hg, and oxygen saturation of 100% on 4 L/min of oxygen. The most likely diagnosis for this patient is toxic shock syndrome, which was later confirmed with a positive antibody test. The initial arterial blood gas (ABG) values are: Such findings are suggestive of metabolic acidosis with respiratory compensation. Further laboratory results are:
A Fully Abstract Semantics and a Proof System for an ALGOL-Like Language with Sharing

In this paper we discuss the semantics of a simple block-structured programming language which allows sharing or aliasing. Sharing, which arises naturally in procedural languages which permit certain forms of parameter passing, has typically been regarded as problematical for the semantic treatment of a language. Difficulties have been encountered in both denotational and axiomatic treatments of sharing in the literature. Nevertheless, we find that it is possible to define a clean and elegant formal semantics for sharing. The key to our success is the choice of semantic model; we show that conventional approaches based on locations are less than satisfactory for the purposes of reasoning about partial correctness, and that in a well defined sense locations are unnecessary.
Policy Data as a Social Process: A Qualitative Approach to Quantitative Data

E VALUATION AND SOCIAL POLICY research have existed for a long time but have proliferated in the last two decades.' Increasingly, social scientists are involved in assessing the impact of social welfare programs such as income maintenance, manpower development, deinstitutionalization, preschool intervention, and "mainstreaming" handicapped youngsters, as well as studying the effects of particular treatment modes (behavior modification, halfway houses, methadone maintenance, parole). In addition, they are involved in assessing the extent and nature of such public concerns as child abuse, violence in schools, handicapped people, and substance abuse, as well as the services available to combat them. The major thrust of such research is based on positivist assumptions and quantitative a n a l y s i ~ . ~ For program evaluation, this means developing operational definitions or program goals (increased I.Q., abstention from drugs, employment), and measuring success against the yardstick of these desired outcomes. In policy research where investigators are assessing the extent and nature of a particular social problem, there is reliance on compilations from official statistics, but data are also generated from random samples of the population or the choice of particular geographic areas to survey, and/or consultation of professionals for estimates of the extent of the problem and the number of people being served. From time to time, social scientists are reminded of the meager reliability of data produced by official agencies (Merton 1957; Seidman and Couzens 1974; Kitsuse and Circourel 1963). For the most part, these critiques have been understood by those who use and create the data as a call to be more methodical, as if the problem were inaccurate counting. In the
CODEPENDENCE OF RENAL CALCIUM AND SODIUM TRANSPORT

Calcium and sodium absorption by the kidney normally proceed in parallel. However, a number of physiological, pharmacological, pathological, and genetic conditions dissociate this relation. In each instance, the dissociation can be traced to the distal convoluted tubule, where calcium and sodium transport are inversely related. Based on the identification of the relevant sodium transporters in these cells and on analysis of the mechanism of calcium transport, an explanation for this inverse relation can be developed. Apical membrane calcium entry is mediated by voltage-sensitive calcium channels that are activated upon membrane hyperpolarization. Basolateral calcium efflux is effected primarily by Na+/Ca2+ exchange. According to the model, inhibition of sodium entry through either the Na-Cl cotransporter or the Na+ channel hyperpolarizes the cell, as does parathyroid hormone, thereby activating the calcium entry channel and increasing the driving force for diffusional entry. Membrane hyperpolarization also increases the driving force of calcium efflux through the Na+/Ca2+ exchanger. Thus sodium-dependent changes of calcium transport are indirect and occur secondarily through effects on membrane voltage.