cssi/SciSciGPT-SciSciNet huggingface dataset:
Approximate Solution to the Sokolovskiĭ Concave Slope at Limiting Equilibrium

AbstractThe growth of precision autoguidance systems on construction equipment suggests that nonplanar slopes and landforms now can be constructed readily. Slopes with concave cross sections not only appear more like natural slopes, but can also have superior stability and erosion resistance. Thus, it is desirable to have the description of concave slopes that provide mechanical stability for a given set of soil properties. In this paper, an approximate solution that defines the geometry of critical concave slopes (factor of safety ≈1) in a frictional medium is developed, based on the slip-line field method. The approximate solution is compared with previous numerical results and validated via limit-equilibrium method and FEM analyses. The proposed solution is simple in form, and, when implemented with precision construction equipment, will allow the construction of embankments and reclaimed mine lands that appear more like those in nature and yet are more resistant to erosion.
Autoradiographic Evaluation of Gingival Response to Injury: V. Surgical Trauma in Low-Protein-Fed Mature Rats

Mature low-protein-fed and control rats received a gingival injury. Healing responses were studied by autoradiographic analysis. Thirty days after injury, malnourished rats showed lower mean labeling indexes than rats fed ad libitum, which suggests that aging and malnutrition may reduce the compensatory response to injury after initial peaks of repair activity are completed.
Proton spectroscopy in asymptomatic HIV-infected adults: Initial results in a prospective cohort study

The purpose of our study was to determine whether proton magnetic resonance spectroscopy (MRS) could detect early brain involvement by human immunodeficiency virus (HIV). We recruited 19 asymptomatic HIV-infected patients, 9 with and 10 without a history of intravenous drug use (IDU), as well as 10 control subjects. All subjects had to have normal MR imaging to be enrolled. We identified the following peaks on proton MRS: n-acetyl aspartate, creatine, choline, and a conglomerate amino acid peak between 2.1 and 2.6 parts per million that we call the marker peaks. Proton MRS was able to demonstrate a statistically significant difference between HIV-infected subjects and controls. The marker/Cr was the best ratio to separate patients from controls, with controls having a mean ratio of 0.50 +/- 0.51 and patients having a mean ratio of 1.8 +/- 0.85 (p = 0.001). There was no difference between HIV-infected subjects with and without a history of IDU. No significant relationship was found between either neuropsychological test scores or CD4 count and metabolite ratios. In brief, MRS seems more sensitive than magnetic resonance imaging (MRI), being able to detect abnormalities in HIV-infected patients when imaging is normal.
Identity of and relationships among certain sour cherry viruses mechanically transmitted to Prunus species.

Abstract Four viruses (A, B, E, and G) isolated from sour cherry (Prunus cerasus L.) were previously differentiated by reactions of herbaceous hosts and by property differences. To identify the viruses as causes of specific cherry diseases, a means of transmitting them from herbaceous hosts to Prunus species was sought. Methods of preparing extracts and inoculating that resulted in greatest infectivity for herbaceous assay plants were used to obtain infection of young seedlings of eight of fifteen Prunus species. P. pennsylvanica L. and P. mahaleb L. were more readily infected than the other species. Graft inoculations from infected seedlings to sour cherry trees showed that virus A was the cause of the recurrent necrotic ringspot disease, while virus G caused ordinary necrotic ringspot of sour cherry. Virus B caused chlorotic spots and rings with slight necrosis, symptoms apparently not previously described in sour cherry. Virus E caused necrotic spotting which somewhat resembled the necrotic ringspot disease, except for the development of enations on the undersides of leaves the year following inoculation. Cross-protection tests in P. pennsylvanica showed that viruses A and G were related strains. Viruses B and E were unrelated to A or G or to each other.
The Combined DNA Index System

The FBI Laboratory has developed the COmbined DNA Index System (CODIS) to assist in resolving crimes, particularly violent crimes, and prevent further crimes by quickly identifying recidivists. CODIS enables laboratories, both nationally and internationally, to exchange and compare DNA profiles electronically, thereby linking crimes committed by the same individual and/ or to convicted offenders whose DNA profiles reside in the databank. In addition to the core short tandem repeat (STR) loci in CODIS, mitochondrial DNA (mtDNA) population data have recently been added. This new component of CODIS, called CODIS MT , will be particularly useful in resolving crimes as well as assisting in the identification of the remains of missing persons. D 2003 Elsevier Science B.V. All rights reserved.
On Derivations and Properties of Stokes' Gravity Formula

Summary Several independent derivations of Stokes' gravity formula have been critically analysed. It is shown that a ‘revised’ Stokes formula derived by R. A. Hirvonen is not valid for gravity data given on an arbitrary surface as claimed, but only for data given on a sphere as in the original Stokes formula. This demonstration invalidates the entire foundation of Hirvonen's New Theory of Gravimetric Geodesy. In derivations based on Poisson's integral theorem a more rigorous treatment of the elimination of zeroth and first order terms of anomalous gravity has been presented. The influence of remote zones in the applications of Stokes' formula has been evaluated by numerical integration. It is shown that tremendous truncation errors occur unless the integration is extended over the entire globe. The differences in truncation error behaviour for different geographical locations are so large that data representing world-wide average behaviour may be very misleading when applied to individual locations. The lack of gravity data coverage over very large parts of the globe causes significant errors in geoidal height determinations and vertical extensions of anomalous gravity by Stokes' formula. In most cases these errors are so large as to render the results virtually meaningless. It is shown that similar drawbacks exist for the calculation of deflexions of the vertical from formulae derived as partial derivatives of the Stokes expression. Significant reduction in the truncation errors is obtained if, following A. H. Cook, a reliable third or higher order spherical harmonic reference model is used in the definition of Δg.
A basic science view of acute kidney injury biomarkers

Over the last decade, significant progress has been made in the identification and validation of novel biomarkers as well as refinements in the use of serum creatinine as a marker of kidney function. These advances have taken advantage of laboratory investigations, which have identified these novel molecules that serve important biological functions in the pathogenesis of acute kidney injury (AKI). As we advance and validate these markers for clinical studies in AKI, we recognize that they serve not only to improve our understanding of AKI, but they could also serve as potential targets for the treatment of AKI. This review will underscore the biological basis of specific biomarkers that will contribute to the advancement in the treatment and outcomes of AKI.
The influence of Coriolis force on surface-tension-driven convection

The effect of uniform rotation on surface-tension-driven convection in an evaporating fluid layer is considered both theoretically and experimentally. The theoretical analysis follows the usual small-disturbance approach of perturbation theory and leads, at the neutral state, to a functional relation between the Marangoni and Taylor numbers which is then computed numerically. In addition, it is shown analytically that, in the limit of rapid rotation, the velocity and temperature fluctuations are confined to a thin Ekman layer near the surface, and that Mc = 4·42T½ and ac = 0·5T¼, where Mc and ac are, respectively, the critical Marangoni number and the critical wave number for neutral stability, and T is the Taylor number.The experimental part deals primarily with the flow pattern of a 50% solution of ethyl ether in n-heptane evaporating into still air. In this case, the convective flow is surface-tension-driven and its structure was observed using schlieren optics. In the absence of rotation, the flow shows a remarkable cellular pattern when the layer is shallow, but when the depth of the layer is increased the pattern quickly becomes highly irregular. In contrast, for T > 103, a cellular structure is always observed even for deep layers, a result which is attributable to the stabilizing effect of the Coriolis force. A further increase in T leaves the flow pattern unchanged except that the size of the cells is found to decrease as T−¼ which is in agreement with the results of the linear stability analysis.
A classroom-administered simulation of a television campaign on adolescent smoking: testing an activation model of information exposure.

In recent years, research has shown that mass media can be used effectively either alone or in conjunction with interpersonal and institutional channels, such as schools. Much has yet been be learned about the application of newer, more effective strategies for media campaigns for adolescent smoking prevention interventions. This article describes a study applying an activation model of information exposure and a sensation-seeking targeting approach to the design of a smoking prevention campaign for adolescents. The participants were 1,272 middle school students aged 12–14 from across the Colorado Front Range who were stratified by their level of sensation seeking and then exposed to both high and low sensation value anti tobacco public service announcements (PSAs) at three time points. Hypothesized effects of the intervention on the primary dependent measures—attitudes (against smoking) and behavioral intentions not to smoke—were strongly supported for high sensation seekers. Further support is offered f...
Adaptive Linear Predictive Coding of Time-Varying Images Using Multidimensional Recursive Least Squares Ladder Filters

This paper presents several adaptive linear predictive coding techniques based upon extension of recursive ladder filters to two and three dimensions (2-D/3-D). A 2-D quarter-plane autoregressive ladder filter is developed using a least square criterion in an exact recursive fashion. The 2-D recursive ladder filter is extended to a 3-D case which can adaptively track the variation of both spatial and temporal changes of moving images. Using the 2-D/3-D ladder filters and a previous frame predictor, two types of adaptive predictor-control schemes are proposed in which the prediction error at each pel can be obtained at or close to a minimum level. We also investigate several modifications of the basic encoding methods. Performance of the 2D/3-D ladder filters, their adaptive control schemes, and variations in coding methods are evaluated by computer simulations on two real sequences and compared to the results of motion compensation and frame differential coders. As a validity test of the ladder filters developed, the error signals for the different predictors are compared and the visual quality of output images is verified.
Histological determination of ozone injury symptoms of primary needles of giant sequoia (Sequoiadendron giganteum Bucch.)

summary Giant sequoia (Sequoiadendron giganteum Bucch.) is a unique resource that exists only in groves on the western slopes of the Sierra Nevada in California. Since Sequoia and King's Canyon (SEKI) National Parks are experiencing ozone concentrations phytotoxic to some species of Pinus, we performed several experiments on S. giganteum seedlings to determine the ozone sensitivity of their primary needles and their suitability as sensitive bioindicators during the seedlings stage of growth. Current-year seedlings were fumigated in open-top chambers during 1986 and 1987. Treatments included (1) carbon-filtered air (no ozone); (2) ambient ozone; (3) 1.5 times the ambient amount of ozone; and (4) a no-chamber treatment. In 1986, ozone doses ranged from 100 to 221 ppm h−1while those in 1987 ranged from 125 to 216 ppm h−1. In neither year did the percentages of plasmolysed cells correlate with ozone dose. In 1986, however, the percentages of amorphously stained and dead cells taken together showed a significant (P= 0.028; r2= 0.721) linear response to dose (y = 29.9 + 0.260x). In the 1987 fumigation, there was no significant relationship between ozone dose and the percentage of either amorphously stained or dead cells. The narrow range of ozone doses (from 125 to 216 ppm h−1) and the short duration of exposure (48 d) may have resulted in high percentages of amorphously stained cells (between 61 and 81 %). In both experimental fumigations, higher ozone doses killed more cells in the needles. When data of the percentages of dead cells from both experiments were pooled, there was a statistically significant (P= 0.0036) correlation coefficient of 0.744 with a line slope of y = 2.472 + 0.051x. There was no evidence of a curvilinear response. The overall anatomy of primary needles from SEKI was similar to that of those sampled from the fumigation experiment; SEKI samples exhibited a high degree of amorphous cell staining (between 67 and 81 %). Cell death averaged 5.1% from all the park samples, a percentage within to the range of cell death (0.9–6.2 %) in the ambient air chambers.
Focus, Transparency and Value: The REIT Evidence

We trace the effects of corporate focus by examining the relationships among focus, cash flows and firm value. In contrast to past studies that examine the effects of diversifying across SIC-code-defined industries, we show that diversification, even within a single industry, reduces value. Our evidence, drawn from a panel of real estate investment trusts, indicates that this reduction is not due to poor managerial performance. Project-level cash flows are actually higher for less focused firms. However, these gains are offset by higher management, administrative and interest expenses. Thus, the corporate cash flows available to shareholders are not related to focus. Finally, we provide empirical evidence that links the effect of focus on value to informational asymmetries which cause the equity of diversified firms to be less liquid. We attribute some of the effect of focus on the cost of both debt and equity to informational asymmetries or transparency costs.
Galois representations attached to representations of GU(3)

For a fixed prime \(\ell\in{\mathbf Z}\) we compute the \(\ell\)-adic Lie algebra of the image of the \(\ell\)-adic Galois representation \(\rho\) attached to a stable cuspidal automorphic representation \(\pi\) of the unitary similitude group GU(3). This result depends on whether \(\pi\) admits extra twists in the sense defined below. Two cases emerge: orthogonal image and non-orthogonal image. We show that in the orthogonal case there exists a character \(\nu\) such that \(\rho\otimes\nu\) is the Galois representation attached to the unitary adjoint lift of a cuspidal representation of GL(2).
A tree-structured algorithm for reducing computation in networks with separable basis functions

I describe a new algorithm for approximating continuous functions in high-dimensional input spaces. The algorithm builds a tree-structured network of variable size, which is determined both by the distribution of the input data and by the function to be approximated. Unlike other tree-structured algorithms, learning occurs through completely local mechanisms and the weights and structure are modified incrementally as data arrives. Efficient computation in the tree structure takes advantage of the potential for low-order dependencies between the output and the individual dimensions of the input. This algorithm is related to the ideas behind k-d trees (Bentley 1975), CART (Breiman et al. 1984), and MARS (Friedman 1988). I present an example that predicts future values of the Mackey-Glass differential delay equation.
Handover performance of HVAC duct based indoor wireless networks

In this paper, we present a performance analysis for different implementations of handover in indoor wireless networks (IWN) that use heating, ventilation, and air conditioning (HVAC) ducts as communication channels. If FDMA/TDMA technology is used, our results show that the handover performance, i.e., new call blocking and handover dropping probabilities, of an IWN that uses HVAC ducts are up to 6.6 times better for practical scenarios compared to those of traditional IWN (i.e., IWN that do not use HVAC ducts). Our results also indicate that for scenarios under investigation, using a single access point to serve one floor and its staircase region achieves the best handover performance for IWN that use HVAC ducts. The solution to the handover problem in HVAC-IWN is tightly coupled with the coverage, capacity, and load balancing issues in indoor wireless networks. We show, for the first time, that the proposed solution to the handover problem in HVAC-IWN results in an increase in capacity per coverage area, an increase in the radius of coverage for an access point, and can be used to achieve load balancing in WLAN that use IEEE 802.11 technology.
An assessment of nitrogen removal from headwater streams in an agricultural watershed, northeast Ohio, U.S.A

The objective of this project was to assess in-stream nitrogen removal capacity in a fragmented agricultural landscape and to compare removal capacities in streams with agricultural or residential (hereafter referred to as agricultural streams) and forested riparian land use. We also identified what stream characteristics control nitrogen removal in these systems. We examined paired reaches (one agricultural and one forested reach) along five headwater streams in an agricultural watershed (Upper Sugar Creek Watershed) in northeast Ohio. Although denitrification rates were high (,0.1–17.2 mg N m22 h21), annual nitrogen removal was most likely low because during spring and fall, when in-stream nitrogen loads were high, removal was low, and during summer when instream nitrogen loads were low, removal was high. Between the agricultural and forested reaches removal rates were similar in terms of loss rate and uptake velocity. Removal capacities were similar despite forested reaches having higher hydraulic residence times. Using a redundancy analysis we identified temperature, in-stream nitrate concentration, and relative transient storage as stream characteristics that affect nitrogen removal. Further analysis suggests that nitrogen removal via denitrification in these headwater streams was not limited by the availability of nitrate. In this fragmented agricultural watershed in-stream nitrogen removal was low and riparian land use had no effect on this process, most likely because of nitrate saturation.
Acceptance of the Dana Medal of the Mineralogical Society of America for 2004

The Dana Medal is a great honor for which I am very grateful to the Mineralogical Society of America, the nominators and the Awards Committee. Receiving an award like this from your peers is a humbling experience. With luck I will continue to live up to its standards. One of the most important benefits is the opportunity to consider the changes in the field that have occurred over a career and the complex interactions among the factors that lead to scientific advancements and successful science. These factors include a great deal of hard work, good fortune, and a local, national and international research environment that promotes scientific excellence. We live in an extraordinary historical period for science, and it has been my great fortune to be able to build my career during that time. When I started, equilibrium thermodynamics was the nearly universal way of thinking about geochemical systems, the electron microprobe was a novel tool, and automated diffractometers were just coming on line. What change there has been! The two parts of my career, the earlier days of crystallization …
ISG20L1 is a p53 family target gene that modulates genotoxic stress-induced autophagy

Autophagy is characterized by the sequestration of cytoplasm and organelles into multimembrane vesicles and subsequent degradation by the cell's lysosomal system. It is linked to many physiological functions in human cells including stress response, protein degradation, organelle turnover, caspase-independent cell death and tumor suppression. Malignant transformation is frequently associated with deregulation of autophagy and several tumor suppressors can modulate autophagic processes. The tumor suppressor p53 can induce autophagy after metabolic or genotoxic stress through transcriptionally-dependent and -independent mechanisms. In this study we expand on the former mechanism by functionally characterizing a p53 family target gene, ISG20L1 under conditions of genotoxic stress. We identified a p53 target gene, ISG20L1, and show that transcription of the gene can be regulated by all three p53 family members (p53, p63, and p73). We generated an antibody to ISG20L1 and found that it localizes to the nucleolar and perinucleolar regions of the nucleus and its protein levels increase in a p53- and p73-dependent manner after various forms of genotoxic stress. When ectopically expressed in epithelial cancer-derived cell lines, ISG20L1 expression decreased clonogenic survival without a concomitant elevation in apoptosis and this effect was partially rescued in cells that were ATG5 deficient. Knockdown of ISG20L1 did not alter 5-FU induced apoptosis as assessed by PARP and caspase-3 cleavage, sub-G1 content, and DNA laddering. Thus, we investigated the role of ISG20L1 in autophagy, a process commonly associated with type II cell death, and found that ISG20L1 knockdown decreased levels of autophagic vacuoles and LC3-II after genotoxic stress as assessed by electron microscopy, biochemical, and immunohistochemical measurements of LC3-II. Our identification of ISG20L1 as a p53 family target and discovery that modulation of this target can regulate autophagic processes further strengthens the connection between p53 signaling and autophagy. Given the keen interest in targeting autophagy as an anticancer therapeutic approach in tumor cells that are defective in apoptosis, investigation of genes and signaling pathways involved in cell death associated with autophagy is critical.
Integrative Neuro-Endocrine Pathways in the Control of Reproduction in Lamprey: A Brief Review

The gonadotropin-releasing hormone (GnRH) system is well known as the main regulator of reproductive physiology in vertebrates. It is also part of a network of brain structures and pathways that integrate information from the internal and external milieu and coordinate the adaptive behavioral and physiological responses to social and reproductive survival needs. In this paper we review the state of knowledge of the GnRH system in relation to the behavior, external, and internal factors that control reproduction in one of the oldest lineage of vertebrates, the lampreys.
A Comparison of the Mechanisms of α-Adrenergic Inhibition of Thyrotropin-Stimulated Adenosine 3′,5′- Monophosphate in Cat, Rat, Mouse, Hamster, Beef, and Pig Tissues with the Stimulatory Effect of Epinephrine on Beef Thyroid Iodination: Evidence for Multiple, Species-Specific Adrenergic Mechanisms*

Epinephrine was shown to inhibit TSH-stimulated cAMP formation in cat and pig thyroid slices and isolated rat and hamster thyroid lobes. In contrast, no such inhibitory action could be demonstrated in sheep or beef thyroid slices or mouse thyroid-trachea preparations. The inhibitory effect of epinephrine on TSH-stimulated cAMP formation in pig thyroid slices was blocked by 10 nM yohimbine, but not by 10 μM prazosin, suggestive of mediation through an α2-catecholamine receptor mechanism. In cat thyroid slices, the inhibitory effect of epinephrine was blocked by both yohimbine and prazosin, suggestive of a mixed a-adrenoceptor mechanism. Meclofenamate and indomethacin attenuated the epinephrine response in cat, but not pig, thyroid slices, but other prostaglandin inhibitors were ineffective. Beef thyroid slices responded to epinephrine with an increase in iodide organification that is mediated through an α-adrenergic mechanism not blocked by propranolol. This stimulatory effect of epinephrine was abolished ...
Estimation of error correlation distance for differential GPS operation

A method for increasing DGPS (differential Global Positioning System) accuracy and operational coverage by adaptively compensating for the changing pseudorange error spatial correlations is presented. These spatial correlations change with time due to atmospheric and geometric variations. Two algorithms for estimating the spatial correlation distances at each ground station are presented. These correlation distances are used in the user receiver's Kalman-based optimal solution of the pseudorange measurement compensations. This increases the operational range and position accuracy by properly accounting for the varying GPS error correlation distances between the ground reference receivers. Simulated examples are used to demonstrate the implementation of this DGPS method. Results showing the added improvements of this approach compared to the constant correlation distance approach are presented. Limitations and suggestions for future research are also discussed. >
Future prospects for genetic manipulation of Rubisco

Recent advances in the development of techniques for the manipulation of gene structure in vitro and genetic transformation of plants have brought the goal of directed genetic modification of RuBP carboxylase-oxygenase (Rubisco) within grasp. Genes from both prokaryotic and eukaryotic species have been cloned, sequenced and expressed in Escherichia coli, and in several instances this has resulted in the production of large quantities of fully functional enzyme. Several specifically-modified enzymes have been produced by site-directed mutagenesis of a cloned gene and the effects of the mutations evaluated following expression of the modified genes in E. coli. Thus, there are no major technical barriers to the creation and analysis of modified enzymes. A number of new opportunities now exist to explore the structural basis of naturally occurring differences in kinetic constants of the enzymes from diverse taxonomic sources. The recent report of chloroplast transformation mediated by the Ti plasmid has also raised the possibility that, if useful natural variation can be identified, genes for both the large and small subunits of the enzyme may eventually be transferred between species. However, the opportunities for rational application of mutagenesis in vitro in the creation of useful or informative variants of the enzyme is currently limited by lack of information about tertiary structure and the role of specific residues in catalysis.
Geometric phase of optical rotators

We describe the rotation of images by means of optical beam steering with use of the concept of geometric phase. The discussion is concentrated on systems composed of discrete reflections but can be generalized to refractive steering systems. Geometric phase reduces the analysis of image rotation to simple geometric constructions and the calculation of areas on a sphere. The analysis also applies to the rotation of linear polarization of the light with ideal mirrors.
Personal Adornment and Expressions of Status: Beads and the Gambia River’s Atlantic Trade

The presence of glass trade beads at Atlantic trade period sites is often thought to provide limited information for the analyst. Several archaeologists working in West Africa have addressed the difficulty of using beads as chronological markers, let alone using these objects to discern local patterns of demand, preference, or consumption. Overall, few scholars have moved beyond the development of descriptive catalogues to determine what information can be ascertained from bead collections other than chronological data. At Juffure on the Gambia River, bead attributes such as shape, color, and size inform the analyst of how change in the demand for and availability of beads were tied to changing local notions of taste and value.
Patents, Antitrust, and the High Cost of Health Care

Americans pay much more for health care than do consumers in other countries, but whether the expense is worth it is, to say the least, debatable. This essay discusses the comparative role of patents, antitrust, and other bodies of law in contributing to the high cost of health care in the United States. I argue that, although patents play a part in raising health care costs, that effect is offset to some degree by substantial countervailing benefits. More troubling has been a two-decade-long failure of antitrust law to prevent anticompetitive hospital mergers and other welfare-reducing practices, though in recent years the courts and agencies have begun to correct some of the worst abuses. Arguably more significant than the failures of either of these two bodies of law, however, are the many ways in which hospitals, drug companies, and other health-related industries often have been able to capture Congress and other entities that supposedly regulate their behavior.
Effect of phosphorus restriction on renal response to oral and intravenous protein loads in rats

Dietary phosphorus restriction ameliorates renal injury in rats. This may be due to changes in renal hemodynamics, including those factors associated with protein-induced hyperfiltration. To test this, we measured inulin clearance (CIn), p-aminohippuric acid clearance (CPAH), mean arterial blood pressure, and renal vascular resistance (RVR) 1 h before and 100 min after either oral gavage of 2 g bovine serum albumin or intravenous infusion of 5% glycine in female Sprague-Dawley rats previously fed for 3-8 wk a 0.5% or a 0.1% phosphorus diet. Baseline CIn, CPAH, blood pressure, and RVR were similar. After albumin gavage, CIn rose 20% (P < 0.01) for the 0.5% phosphorus group but did not change for rats fed the 0.1% phosphorus diet. Other measured parameters, including plasma glucagon and renin activity, were not influenced by dietary phosphorus content. In contrast, during intravenous infusion of glycine, hyperfiltration was induced in phosphorus-restricted rats. Thus dietary phosphorus restriction ablates oral protein but not intravenous amino acid-induced hyperfiltration, suggesting a gut-mediated mechanism for the former. These data highlight the potential importance of dietary phosphorus as a mediator of renal hemodynamics.
Ef-Current Contributes to Whole-Cell Calcium Current in Low Calcium in Frog Sympathetic Neurons

Because Ca2+ plays diverse roles in intracellular signaling in neurons, several types of calcium channels are employed to control Ca2+ influx in these cells. Our experiments focus on resolving the paradox of why whole-cell current has not been observed under typical recording conditions for one type of calcium channel that is highly expressed in frog sympathetic neurons. These channels, referred to as Ef-channels, are present in the membrane at a density greater than the channels that carry ∼90% of whole-cell current in low Ba2+; but, Ef-current has not been detected in low Ba2+. Using Ca2+ instead of Ba2+ as the charge carrier, we recorded a possible E-type current in frog sympathetic neurons. The current was resistant to specific blockers of N-, L-, and P/Q-type calcium channels but was more sensitive to Ni2+ block than was N- or L-current. Current amplitude in Ca2+ is slightly greater than that in Ba2+. In 3 mM Ca2+, the current contributed ∼12% of total current at peak voltage and increased at voltage...
Time Smart

Those who "invest" and "spend" their time wisely will have greater success than those who haven't learned this valuable skill. Find out how to effectively manage your time to maximize the return on your investment.
Of Aeronautics, Aerophysics, and Aerospace: Aerospace Engineering at Mississippi State University

*The study of aeronautical engineering at Mississippi State University began in 1933. This paper traces this history of the Department from its founding through the war years, the boom years in the 1950s and 1960s, the downturn of the 1970s, and the recovery in the 1980s. This paper describes the origins of the Raspet Flight Research Laboratory, the National Science Foundation Engineering Research Center for Computational Field Simulation, and the Diagnostic Instrumentation and Analysis Laboratory. The history of the world’s first all-composite aircraft, the MARVEL, is also discussed.
Intentional poisoning of birds with parathion

-Intentional poisoning of birds by farmers is not uncommon but is rarely documented and given proper attention. Two recent cases from New York are illustrative. In the first, at least 5,120 birds, mostly Red-winged Blackbirds (Ageu Tucker and Crabtree 1970, Schafer 1972). Accidental deaths of numerous wild birds have resulted from the agricultural use of parathion. White et al. (1982a, b) reported the deaths of over 1,600 waterfowl, mostly Canada Geese (Branta canadensis), from applications of parathion to agricultural fields in Texas. More insidious and less appreciated is the use of parathion to deliberately poison wild birds. Carson (1962) described the purposeful killing, by farmers, of an estimated 65,000 birds with parathion. Farmers continue to intentionally kill birds with parathion and this report describes the investigation of two recent cases in New York State.
A mathematical model of the outer medullary collecting duct of the rat

A mathematical model of the outer medullary collecting duct (OMCD) has been developed, consisting of α-intercalated cells and a paracellular pathway, and which includes Na+, K+, Cl−, HCO3 −, CO2, H...
Adolescents, Family History, and Inherited Disease Risk: An Opportunity.

A teenager recently presented to my clinic for a well visit, accompanied by his mother. He had no complaints, and his examination was unremarkable, but a family history revealed familial adenomatous polyposis in his mother; a recent genetic test had identified her causal mutation. Despite his risk of heritable, early-onset colon cancer (and his desire to know whether he carried the same mutation as his mother) the boy had not yet been evaluated. As I scheduled him for subspecialty follow-up, I considered what had occurred at this primary care visit: Simple questions about family medical history in the presence of a parent had revealed a potential disease risk in the boy and his future children, had suggested testing and surveillance to clarify and reduce this risk, and had empowered him to think about and participate in his own health care. To know one’s own family health history is a valuable commodity; it holds clues to disease predisposition both for an individual and for his or her children. Learning about one’s own early childhood medical history is similarly important. Despite evidence endorsing iterative collection of family history over time,1 it is discussed at a minority of established patients’ well visits to generalist physicians,2 suggesting the need for guidance as to when family health history should be ascertained. The aforementioned vignette illustrates that the teenage years are an ideal time for family and personal health history to be imparted and discussed. Teenagers are old enough … Address correspondence to Philip M. Boone, MD, PhD, Boston Children’s Hospital, 300 Longwood Ave, Boston, MA 02115. E-mail: philip.boone{at}childrens.harvard.edu
Association between volume and momentum of online searches and real-world collective unrest

Abstract A fundamental idea from physics is that macroscopic transitions can occur as a result of an escalation in the correlated activity of a many-body system’s constituent particles. Here we apply this idea in an interdisciplinary setting, whereby the particles are individuals, their correlated activity involves online search activity surrounding the topics of social unrest, and the macroscopic phenomenon being measured are real-world protests. Our empirical study covers countries in Latin America during 2011–2014 using datasets assembled from multiple sources by subject matter experts. We find specifically that the volume and momentum of searches on Google Trends surrounding mass protest language, can detect – and may even pre-empt – the macroscopic on-street activity. Not only can this simple open-source solution prove an invaluable aid for monitoring civil order, our study serves to strengthen the increasing literature in the physics community aimed at understanding the collective dynamics of interacting populations of living objects across the life sciences.
Performance-optimized optical bidirectional backplane bus for multiprocessor systems

We review the recent results on the design and implementation of the performance-optimized bidirectional optical backplane bus aimed at high speed multiprocessor systems. It employs an array of multiplexed holograms, in conjunction with a waveguiding plate within which cascaded fanouts are generated. Data transfer rate of 1.2 Gbit/sec at 1300 nm is demonstrated with a single bus line for a system composed of nine boards. Packaging-related issues and misalignment effects are addressed. Theoretical treatment to minimize fluctuations among the received powers at each board was carried out and the overall performance was optimized. We also introduce a hybrid optical backplane with multiple bus lines. The hybrid backplane maintains the same waveguiding structure, and exploits optoelectronic array devices. A new demonstration system is being implemented. The optical backplane that we developed is transparent to higher level bus protocols, thus can support standard backplane buses such as Futurebus+, Multibus II, and VMEbus.
Validity of Radionuclide Cerebral Angiography for Diagnosing Brain Death in Infants

Since 1969, we have been using intravenous (IV) radionuclide cerebral angiography (RCA) as a confirmatory test for brain death in both children and adults (Goodman and Heck, 1977; Goodman et al., 1969, 1985). However, a recent highly respected consensus report (Report of the Medical Consultants on the Diagnosis of Death, 1981) has advised caution in using adult-based criteria for determining brain death in children, implying that a young child with a severe neurological insult may have greater recovery potential than an adult in a similar situation. In order to respond to concerns raised about the validity of RCA in diagnosing brain death in very young patients, we have reviewed our recent results with this technique in infants under 2 years with suspected brain death.
Stable Mono- and Dinuclear Organosilver Complexes

A series of mononuclear and dinuclear complexes of silver(I), supported by an N-heterocyclic carbene and bound to sp3-, sp2-, and sp-hybridized carbanions, has been synthesized. Synthetic routes include transmetalation from organozinc, organomagnesium, and organosilicon reagents, as well as the deprotonation of a terminal alkyne. These complexes exhibit greater thermal stability than typical organosilver reagents, permitting spectroscopic and structural characterization. The carbanion-bridged disilver cations feature three-center, two-electron bonding with short Ag···Ag distances. A mononuclear vinylsilver complex releases organic homocoupling products upon thermal decomposition, while mononuclear alkylsilver complexes exhibit nucleophilic behavior, for example, inserting CO2 to form silver carboxylates.
Commentary: Future U.S. National Statistics Use of Administrative Data

Government statisticians are intrigued by the possibility of accessing administrative data as a way to enhance survey and census data. Survey data are rich in attributes, but they exhibit sampling errors. More consequentially, they demonstrate non-sampling errors, often because of nonresponse, but also because of responses that are incomplete or inaccurate, frequently due to the respondent’s inability to recall. Additionally, panel data are subject to attrition. Administrative data can help compensate for these problems importantly because administrative data, such as social security files, include almost everybody. Further, supplementing statistical data can be cost-effective, because an enormous amount of administrative data are already collected to support the functional operations of government agencies, and so are potentially available. In many instances, respondent burden in surveys can be lessened because certain attribute values may be available from administrative records. Some U.S. federal agencies, e.g., the Social Security Administration (McNabb et al., 2009) have linked administrative data with survey data to broaden its demographic and socioeconomic measures and also to improve the quality of the survey data. See National Research Council (2005), pp.45–48 for additional examples and discussion of benefits of such data linkage.
Purging putative siblings from population genetic data sets: a cautionary view.

Interest has surged recently in removing siblings from population genetic data sets before conducting downstream analyses. However, even if the pedigree is inferred correctly, this has the potential to do more harm than good. We used computer simulations and empirical samples of coho salmon to evaluate strategies for adjusting samples to account for family structure. We compared performance in full samples and sibling-reduced samples of estimators of allele frequency (P^), population differentiation (F^ST) and effective population size (N^e). RESULTS (i) unless simulated samples included large family groups together with a component of unrelated individuals, removing siblings generally reduced precision of P^ and F^ST; (ii) N^e based on the linkage disequilibrium method was largely unbiased using full random samples but became increasingly upwardly biased under aggressive purging of siblings. Under nonrandom sampling (some families over-represented), N^e using full samples was downwardly biased; removing just the right 'Goldilocks' fraction of siblings could produce an unbiased estimate, but this sweet spot varied widely among scenarios; (iii) weighting individuals based on the inferred pedigree (to produce a best linear unbiased estimator, BLUE) maximized precision of P^ when the inferred pedigree was correct but performed poorly when the pedigree was wrong; (iv) a variant of sibling removal that leaves intact small sibling groups appears to be more robust to errors in inferences about family structure. Our results illustrate the complex challenges posed by presence of family structure, suggest that no single optimal solution exists and argue for caution in adjusting population genetic data sets for the presence of putative siblings without fully understanding the consequences.
Introduction: Seniors Housing

(1999). Introduction: Seniors Housing. Journal of Real Estate Portfolio Management: Vol. 5, No. 3, pp. 201-202.
Pencil Beam Algorithms Are Unsuitable for Proton Dose Calculations in Lung.

Purpose To compare analytic and Monte Carlo–based algorithms for proton dose calculations in the lung, benchmarked against anthropomorphic lung phantom measurements. Methods and Materials A heterogeneous anthropomorphic moving lung phantom has been irradiated at numerous proton therapy centers. At 5 centers the treatment plan could be calculated with both an analytic and Monte Carlo algorithm. The doses calculated in the treatment plans were compared with the doses delivered to the phantoms, which were measured using thermoluminescent dosimeters and film. Point doses were compared, as were planar doses using a gamma analysis. Results The analytic algorithms overestimated the dose to the center of the target by an average of 7.2%, whereas the Monte Carlo algorithms were within 1.6% of the physical measurements on average. In some regions of the target volume, the analytic algorithm calculations differed from the measurement by up to 31% in the internal gross target volume (iGTV) (46% in the planning target volume), over-predicting the dose. All comparisons showed a region of at least 15% dose discrepancy within the iGTV between the analytic calculation and the measured dose. The Monte Carlo algorithm recalculations showed dramatically improved agreement with the measured doses, showing mean agreement within 4% for all cases and a maximum difference of 12% within the iGTV. Conclusions Analytic algorithms often do a poor job predicting proton dose in lung tumors, over-predicting the dose to the target by up to 46%, and should not be used unless extensive validation counters the consistent results of the present study. Monte Carlo algorithms showed dramatically improved agreement with physical measurements and should be implemented to better reflect actual delivered dose distributions.
Identifying and Addressing the Mental Health Needs of Online Students in Higher Education

“In a traditional classroom setting faculty have the ability to visually observe students, and interact face to face. This direct, experiential contact with students enables faculty to perceive mental health warning signs such as deterioration in hygiene, tardiness and absences, mood changes, bizarre behaviors, and altered levels of attention. In online educational settings the direct sensory contact with students is missing and the student is often at a distant geographic location. Thus, online educators need strategies for identifying mental health problems in their students, resources available to offer the distance student, and institutional policies addressing mental health and student performance. This article focuses on these topics.”...
Molecular Basis for Olefin Rearrangement in the Gephyronic Acid Polyketide Synthase.

Polyketide synthases (PKS) are a rich source of natural products of varied chemical composition and biological significance. Here, we report the characterization of an atypical dehydratase (DH) domain from the PKS pathway for gephyronic acid, an inhibitor of eukaryotic protein synthesis. Using a library of synthetic substrate mimics, the reaction course, stereospecificity, and tolerance to non-native substrates of GphF DH1 are probed via LC-MS analysis. Taken together, the studies establish GphF DH1 as a dual-function dehydratase/isomerase that installs an odd-to-even double bond and yields a product consistent with the isobutenyl terminus of gephyronic acid. The studies also reveal an unexpected C2 epimerase function in catalytic turnover with the native substrate. A 1.55-A crystal structure of GphF DH1 guided mutagenesis experiments to elucidate the roles of key amino acids in the multistep DH1 catalysis, identifying critical functions for leucine and tyrosine side chains. The mutagenesis results were a...