cssi/SciSciGPT-SciSciNet huggingface dataset:
Hypothalamic-Pituitary-Ovarian Axis and Control of the Menstrual Cycle

Menstruation is the cyclic and orderly sloughing of the endometrium. In order for normal menstruation to take place, a complex interaction between the brain, the ovaries, and the uterus has to take place. This interaction involves fluctuating levels of hormones produced by the brain as well as the ovaries, while the uterus responds to the changing hormone levels. This process of hormone production is initiated in the hypothalamus through the production and release of GnRH, which leads to FSH and LH release from the anterior pituitary gland. As a result, oocyte development takes place in the ovaries, and estradiol is produced from the growing ovarian follicle. As the growing follicle matures and estradiol rises further, LH from the pituitary surges, leading to the process of ovulation. After ovulation, the remnant of the follicle becomes the corpus luteum, which is responsible for progesterone production. If the cycle does not result in a pregnancy, progesterone levels decline and menstruation takes place. Throughout this process, there are many other hormones from the central nervous system as well as from the ovary that play a role in the control of the menstrual cycle. We will examine the role of the central nervous system and how it interacts with the ovaries to control the menstrual cycle.
Highly efficient 5G linear power amplifiers (PA) design challenges

The incoming 5G revolution will dramatically increase the design complexity for handsets and communication infrastructures, demanding the RFIC and ASIC chipsets designers, network and system components vendors and telecom operators to provide viable 5G E2E (End-to-End) products and solutions before A.D. 2020. The broadband modulation bandwidth for RF transmitters (i.e., 250 MHz to above 1 GHz), stringent linearity, and power efficiency requirements at the cm-Wave/mm-Wave 5G frequencies will make it particularly challenging for highly efficient linear 5G power amplifier (PA) design. We will briefly address two major design challenges and solutions for 5G PA design here, namely the device technology choices and efficiency enhancement techniques.
Cortical-hippocampal functional connectivity during covert consolidation sub-serves associative learning: Evidence for an active “rest” state

Abstract We studied modulation of undirected functional connectivity (uFC) in cortical-hippocampal sub-networks during associative learning. Nineteen healthy individuals were studied (fMRI acquired on a Siemens Verio 3T), and uFC was studied between nodes in a network of regions identified by standard activation models based on bivariate correlational analyses of time series data. The paradigm alternated between Memory Encoding, Rest and Retrieval. “Rest” intervals promoted covert consolidation. Over the task, performance was broadly separable into linear (Early) and asymptomatic (Late) regimes, with late performance reflecting successful memory consolidation. Significant modulation of uFC was observed during periods of covert consolidation. The sub-networks which were modulated constituted connections between frontal regions such as the dorsal prefrontal cortex (dPFC) and dorsal anterior cingulate cortex (dACC), the medial temporal lobe (hippocampus, HPC), the superior parietal cortex (SPC) and the fusiform gyrus (FG). uFC patterns were dynamic in that sub-networks modulated during Early learning (dACC ↔ SPC, dACC ↔ FG, dPFC ↔ HPC) were not identical to those modulated during Late learning (dACC ↔ HPC, dPFC ↔ FG, FG ↔ SPC). Covert consolidation exerts systematic effects, and these results add to emerging evidence for the constructive role of the brain’s “resting state” in potentiating action.
Brillouin Scattering from Superfluid 3He-4He Mixtures*

We are using Brillouin scattering to study thermally excited first sound. second sound, and concentration fluctuations in superfluid 3He-4He mixtures. The spectrum of the scattered light consists of five lines. One pair of lines arises from first sound and is shifted from the incident laser frequency by an amount v, Ku t /2n,where u t is the velocity of first sound and K is the scattering wave vector. The half-width at half-height of the lines 6v t is a measure of the amplitude attenuation coefficient a of first sound at that frequency: Sy,cqu t /21t. Another pair of lines results from scattering by second sound. The frequency shift of these lines is v2 Ku 2 /27r and their half-width is given by Sv2 a 2 u 2 /2n,where u2 and a2 are the velocity and attenuation coefficient of second sound, respectively. The fifth line is due to the presence in the mixture of concentration fluctuations at constant pressure. This line is not shifted in frequency relative to the incident light, indicating that concentration fluctuations do not propagate but merely decay away. The decay time constant is inversely proportional to the width of the unshifted line.
The Hierarchical Bayesian Approach

It is essential at the outset to be clear about what is and what is not a Bayesian approach. In particular, none of the credibility methods being used at this time qualify as true Bayesian analyses. The requirements as introduced in Chapter 2 are few — a prior probability distribution that is determined before the data are collected and a model probability distribution. What we need to do for the credibility problem is identify just where these two items come in.
A Framework For Studying The RKEM Representation of Discrete Point Sets

The application of engineering analysis to new areas, such as nanomechanics and the life sciences, often involves geometric problem domains defined by discrete point sets as measured from diagnostic equipment. The development of a suitable mesh for finite element analysis can be a tedious task. One approach to simplifying the geometric description is to use a parametrized set of basis functions, and fit the parameters to the data set. In this paper, we discuss the problem of determining suitable parameters for the Reproducing Kernel Element Method representation of discrete point sets, and in particular the solution of the inverse problem of determining pre-image evaluation points in the parametric space that correspond to a given input point. We justify our solution by posing a theoretical framework and an error indicator.
Abstract 178: A Shocking Inefficiency: Unexpected Cancellations of Elective Cardioversions at a High Volume Electrophysiology Lab

Background: Despite advances in pharmacologic therapies and ablation techniques, elective cardioversions (CV) remain integral to the care of patients with atrial fibrillation (AF). These outpatient procedures require appropriate patient preparation to maintain patient safety and maximize success rates. These preparations include confirming adequate anticoagulation and pre-CV heart rhythm recording. Despite these preparations, unexpected cancellations of CV occur and lead to patient dissatisfaction and lost productivity. The objective of this study was to examine the frequency and cause of unexpected CV cancellations in a large volume center and to assess how novel technologies may improve efficiency in the future. Methods: Patients with AF who presented for scheduled elective CV were screened consecutively for enrollment. All patients were contacted the day before CV to confirm adequate anticoagulation and to provide instructions regarding fasting and the use of medications the morning of the planned CV. Information regarding the patients’ anticoagulation strategies and history were recorded at the time of enrollment. INR levels were obtained using routine serum and point of care testing. Statistical analysis was performed to evaluate trends in cancelled CV, potential impacts on the EP lab and to assess the ability of mobile technology to improve the CV process. Results: Two hundred patients were enrolled (Age 68 ± 12). Anticoagulation strategies varied in this group and included apixaban (N=90), warfarin (N=73), rivaroxaban (N=35) and dabigatran (N=2). Three patients required unplanned transesophageal echocardiogram. Thirty-two patients presented for CV but had their procedure cancelled due to a subtherapeutic INR (N=5), supratherapeutic INR (N=2), being in normal sinus rhythm (N=14), thrombus present on TEE (N=5) and intolerance of the TEE (N=2). CV was successful in 96% of patients (N=192). Point of care testing (POCT) and standard serum measurements were strongly correlated (r=0.961, p Conclusions: A shocking percentage of CV are cancelled unexpectedly highlighting an opportunity to improve efficiency and productivity in the EP lab. The cancellations appear to be driven by inadequate anticoagulation and patients unexpectedly arriving in normal sinus rhythm. Technology providing remote assessment of both of these clinical variables is already commercially available. This remote monitoring of heart rhythm and INR may provide opportunities to reduce cancellations, improve patient satisfaction and boost EP lab productivity.
Women’s business ownership and women’s entrepreneurship through the lens of U.S. federal policies

Although the USA is at the forefront of nations promoting women’s business ownership and entrepreneurship, the role of U.S. federal policies in supporting these goals remains unexamined. This study examines six decades (1951–2011) of U.S. Federal Statutes to answer the research question—how do U.S. federal policies support women’s business ownership and women’s entrepreneurship? The study methodology includes quantitative and qualitative analysis of federal laws and resolutions. The quantitative analysis suggests that in 1988, with the passage of the Women’s Business Ownership Act, the USA began to intensify policy interest in this area. What began as policy experimentation in 1988 gradually became institutionalized. The qualitative analysis suggests that in terms of broad policy intent and intended outcomes not much has changed since 1988. Given this sobering finding, we discuss important implications and future research questions to motivate stronger research on how government can better support women business owners and entrepreneurs.
Erratum to “Pathogen discovery from human tissue by sequence-based computational subtraction”

a Department of Adult Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA b Whitehead Institute/MIT Center for Genome Research, Cambridge, MA 02142, USA c Decision Systems Group, Brigham and Women’s Hospital, Boston, MA 02115, USA d Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA e Department of Pathology, Harvard Medical School, Boston, MA 02115, USA f Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02138, USA
THE ARRANGEMENT, REARRANGEMENT AND ORIGIN OF IMMUNOGLOBULIN GENES

Publisher Summary This chapter analyzes the arrangement, rearrangement, and origin of immunoglobulin genes. The immune system requires sufficient genetic information to encode approximately a million different antibody molecules, each exhibiting remarkable specificity with respect to the antigens that it binds. These antibody molecules comprised of pairs of heavy and light chains display an interesting structural feature wherein their 100 or so N-terminal amino acids differ from antibody chain to antibody chain while their C-terminal portions remain identical in primary amino acid sequence. In a study described in this chapter, the tetrasegmental structure of kappa light chain genes was examined. Immunoglobulin kappa variable region genes constitute a multiple gene family that has arisen through evolution and now consists of many small subfamilies of variable region genes that are closely related both in their structure and flanking sequences. The chapter analyzes the possible role of unequal-crossing in generating immunoglobulin gene diversity. It is illustrated in the chapter that the kappa light chain genes of the mouse are encoded as four separate genetic elements. The first two comprise a large set of split variable region genes encoding a major portion of antibody diversity.
Sound quality metric indicators of rotorcraft noise annoyance using multilevel regression analysis

It is hypothesized that sound quality metrics, particularly loudness, sharpness, tonality, impulsiveness, fluctuation strength, and roughness, could all be possible indicators of the reported annoyance to helicopter noise. To test this hypothesis, a psychoacoustic test was recently conducted in which subjects rated their annoyance levels to synthesized helicopter sounds [Krishnamurthy, InterNoise2018, Paper 1338]. After controlling for loudness, linear regression identified sharpness and tonality as important factors in predicting annoyance, followed by fluctuation strength. Current work focuses on multilevel regression techniques in which the regression slopes and intercepts are assumed to take on normal distributions across subjects. The importance of each metric is evaluated one-by-one, and the variation among subjects is evaluated using simple models. Then, more complete models are investigated, which include the combination of selected metrics and subject-specific effects. While the conclusions from linear regression analysis are affirmed by multilevel analysis, other important effects emerge. In particular, variable intercepts are shown to be more important than variable slopes. In this framework, the relative importance of sound quality metrics is re- examined, and the potential for the modeling of human annoyance to helicopter noise based on sound quality metrics is explored.
Identifying and Developing Crosscutting Environmental Education Outcomes for Adolescents in the Twenty-First Century (EE21).

While multiple valid measures exist for assessing outcomes of environmental education (EE) programs, the field lacks a comprehensive and logistically feasible common instrument that can apply acros...
A Data-Driven Game-Theoretic Approach for Behind-the-Meter PV Generation Disaggregation

Rooftop solar photovoltaic (PV) power generator is a widely used distributed energy resource (DER) in distribution systems. Currently, the majority of PVs are installed behind-the-meter (BTM), where only customers’ net demand is recorded by smart meters. Disaggregating BTM PV generation from net demand is critical to utilities for enhancing grid-edge observability. In this paper, a data-driven approach is proposed for BTM PV generation disaggregation using solar and demand exemplars. First, a data clustering procedure is developed to construct a library of candidate load/solar exemplars. To handle the volatility of BTM resources, a novel game-theoretic learning process is proposed to adaptively generate optimal composite exemplars using the constructed library of candidate exemplars, through repeated evaluation of disaggregation residuals. Finally, the composite native demand and solar exemplars are employed to disaggregate solar generation from net demand using a semi-supervised source separator. The proposed methodology has been verified using real smart meter data and feeder models.
High-Need Phenotypes in Medicare Beneficiaries: Drivers of Variation in Utilization and Outcomes.

OBJECTIVES High-need (HN) Medicare beneficiaries heavily use healthcare services at a high cost. This population is heterogeneous, composed of individuals with varying degrees of medical complexity and healthcare needs. To improve healthcare delivery and decrease costs, it is critical to identify the subpopulations present within this population. We aimed to (1) identify distinct clinical phenotypes present within HN Medicare beneficiaries, and (2) examine differences in outcomes between phenotypes. DESIGN Latent class analysis was used to identify phenotypes within a sample of HN fee-for-service (FFS) Medicare beneficiaries aged 65 years and older using Medicare claims and post-acute assessment data. SETTING Not applicable. PARTICIPANTS Two cross-sectional cohorts were used to identify phenotypes. Cohorts included FFS Medicare beneficiaries aged 65 and older who survived through 2014 (n = 415 659) and 2015 (n = 416 643). MEASUREMENTS The following variables were used to identify phenotypes: acute and post-acute care use, functional dependency in one or more activities of daily living, presence of six or more chronic conditions, and complex chronic conditions. Mortality, hospitalizations, healthcare expenditures, and days in the community were compared between phenotypes. RESULTS Five phenotypes were identified: (1) comorbid ischemic heart disease with hospitalization and skilled nursing facility use (22% of the HN sample), (2) comorbid ischemic heart disease with home care use (23%), (3) home care use (12%), (4) high comorbidity with hospitalization (32%), and (5) Alzheimer's disease/related dementias with functional dependency and nursing home use (11%). Mortality was highest in phenotypes 1 and 2; hospitalizations and expenditures were highest in phenotypes 1, 3, and 4. CONCLUSIONS Our findings represent a first step toward classifying the heterogeneity among HN Medicare beneficiaries. Further work is needed to identify modifiable utilization patterns between phenotypes to improve the value of healthcare provided to these subpopulations. J Am Geriatr Soc 68:70-77, 2019.
Evidence-Based Interventions that Promote Resident Wellness from the Council of Emergency Residency Directors

Initiatives for addressing resident wellness are a recent requirement of the Accreditation Council for Graduate Medical Education in response to high rates of resident burnout nationally. We review the literature on wellness and burnout in residency education with a focus on assessment, individual-level interventions, and systemic or organizational interventions.
A Preterm Infant with a Characteristic Erythematous and Scaly Rash After Birth.

A preterm infant born at 26 weeks’ gestational age presents with a rash that evolves into an erythematous and scaly rash on the second day after birth (Figs 1–4). Figure 1. Scaly and erythematous rash over the arm, day 2 after birth. Figure 2. Scaly and erythematous rash over the back, day 2 after birth. Figure 3. Rash over the chest and abdomen, day 2 after birth. Note that the rash is not as pronounced on the trunk as it is on the back and arms. Figure 4. Rash over the chest and abdomen, day 2 after birth. Note that the rash is not as pronounced on the trunk as it is on the back and arms. ### Prenatal and Birth History ### Presentation At delivery, the infant emerged limp and had persistent apnea that required positive pressure ventilation followed by endotracheal intubation. She was transferred to the NICU, where she received 1 dose of endotracheal surfactant and the …
Fast Attack-Resilient Distributed State Estimator for Cyber-Physical Systems

The performance of resilient state estimators developed for cyber-physical systems (CPSs) decreases as the number of compromised sensors of the system increases. Furthermore, some of these algorithms leverage computationally expensive optimization techniques to incorporate resiliency. As such, we propose a fast resilient distributed state estimator (FRDSE), which is a novel resilient distributed algorithm that produces bounded state estimation errors regardless of the magnitude of the attack and the number of compromised sensors. Our algorithm converges to the true state in an attack-free and noise-free scenario and it produces bounded estimation errors during an attack. Compared to existing algorithms, FRDSE is more computationally efficient. We provide theoretical guarantees on the convergence of FRDSE in attack-free scenario and prove its resiliency during an attack. We demonstrate the performance of our algorithm against false data injection (FDI) attack in a platoon of vehicles and compare its runtime against existing algorithms. We observe that on a platoon of eight vehicles, runtime of our algorithm is 0.102 s, much lower than the state-of-the-art solutions.
Renal-Cerebral Pathophysiology: The Interplay Between Chronic Kidney Disease and Cerebrovascular Disease.

Abstract Objectives Cerebrovascular disease has increasingly been linked to overall vascular health. Pathologic conditions like diabetes, hypertension, and kidney disease have been shown to affect brain health and cerebrovascular and nervous systems. Acute kidney injury (AKI) and chronic Kidney Disease (CKD) represent a variety of vascular insults that can adversely affect cerebral health. Hypertension, fluctuations in blood pressure, and diabetic vasculopathy are known risk factors for cerebrovascular disease associated with CKD. Other emerging areas of interest include endothelial dysfunction, vascular calcification due to calcium and phosphorus metabolism dysregulation, and uremic neuropathy present the next frontier of investigation in CKD and cerebrovascular health. Methods It has become apparent that the interrelation of AKI and CKD with vascular health, chemical homeostasis, and hormonal regulation upset many aspects of cerebral health and functioning. Stroke is an obvious connection, with CKD patients demonstrating a higher proclivity for cerebrovascular accidents. Cerebral bleeding risk, uremic neuropathies, sodium dysregulation with impacts on nervous system, vascular calcification, and endothelial dysfunction are the next salient areas of research that are likely to reveal key breakthroughs in renal-cerebral pathophysiology. Results In this review nephrological definition are discussed in a neuro-centric manner, and the areas of key overlap between CKD and cerebrovascular pathology are discussed. The multifaceted effects of renal function on the health of the brain are also examined. Conclusion This review article aims to create the background for ongoing and future neurological-nephrological collaboration on understanding the special challenges in caring for patients with cerebrovascular disease who also have CKD.
Persistence of choking injuries in children

Abstract Background Choking injuries are a significant cause of morbidity and mortality in children and represent a significant public health concern. Evaluating trends and the impact of interventions are essential to highlight whether progress has been made and to target public health efforts. Objective To investigate how rates of nonfatal and fatal choking injuries have changed before and after 2010 when policy recommendations were made by the American Academy of Pediatrics. Methods A descriptive study investigating unintentional nonfatal and fatal choking injuries in children aged 0–19 years using national data from 2001 to 2016 through the Centers for Disease Control and Prevention's WISQARS™ and WONDER databases, focusing on the 6 years prior and 6 years after release of the AAP's recommendations. The data was categorized by age, gender, year, and race/ethnicity for descriptive and statistical analyses. Results From 2001 to 2016, there were a total of 305,814 nonfatal injuries and 2347 choking deaths in children from 0 to 19 years. Children under five years of age accounted for 73% of nonfatal injuries and 75% of choking fatalities. There was a statistically significant increase in the nonfatal injuries rate when comparing 2005–2010 and 2011–2016 (19/100,000 versus 26/100,000, respectively). There was a decrease in the choking fatalities rate in all children (0.18/100,000 versus 0.16/100,000, respectively) but no change in fatalities rate for children under five. White and Black children experience nonfatal choking injuries at a higher rate than Hispanics. Black children had highest rates of choking fatalities over Hispanic, White, Asian, and Alaskan or American Indian ethnicities. The lowest rates of death occurred in Asians. Conclusions Overall rate of nonfatal choking injuries increased, while rate of choking fatalities in children decreased after 2010. However, the choking fatalities rate in 0–4 years olds, the highest risk group, did not change. Racial gaps exist with highest rates of injury in Black children. We must continue to educate and raise awareness of choking injuries, with targeted efforts to address racial disparities.
A comprehensive temporal patterning gene network in Drosophila medulla neuroblasts revealed by single-cell RNA sequencing

During development, neural stem cells are temporally patterned to sequentially generate a variety of neural types before exiting the cell cycle. Temporal patterning is well-studied in Drosophila, where neural stem cells called neuroblasts sequentially express cascades of Temporal Transcription Factors (TTFs) to control the birth-order dependent neural specification. However, currently known TTFs were mostly identified through candidate approaches and may not be complete. In addition, many fundamental questions remain concerning the TTF cascade initiation, progression, and termination. It is also not known why temporal progression only happens in neuroblasts but not in their differentiated progeny. In this work, we performed single-cell RNA sequencing of Drosophila medulla neuroblasts of all ages to study the temporal patterning process with single-cell resolution. Our scRNA-seq data revealed that sets of genes involved in different biological processes show high to low or low to high gradients as neuroblasts age. We also identified a list of novel TTFs, and experimentally characterized their roles in the temporal progression and neural fate specification. Our study revealed a comprehensive temporal gene network that patterns medulla neuroblasts from start to end. Furthermore, we found that the progression and termination of this temporal cascade also require transcription factors differentially expressed along the differentiation axis (neuroblasts -> -> neurons). Lola proteins function as a speed modulator of temporal progression in neuroblasts; while Nerfin-1, a factor required to suppress de-differentiation in post-mitotic neurons, acts at the final temporal stage together with the last TTF of the cascade, to promote the switch to gliogenesis and the cell cycle exit. Our comprehensive study of the medulla neuroblast temporal cascade illustrated mechanisms that might be conserved in the temporal patterning of neural stem cells.
Dielectric Lens Designs for Antenna Beam Shaping in a Subdermal Tumor Treatment Device

Planar diverging lenses attached to the front end of a dielectric rod antenna are proposed to control the heating area on the human body to assist the electroporation treatment of different tumor sizes. The desired 5–7 °C temperature elevation of the tumors is achieved in 3 minutes by applying 2.1-3.6 W input power depending on the size of tumor. In order to treat the tumors located 3–7 mm below the skin surface, the applicator is operated at 8 GHz. The experimental results obtained by measuring a pork muscle tissue show good agreement with electro-thermal simulations.
Anatomy of Gene Regulation: Transcription in Prokaryotes

PRIMER Unwinding of DNA is not only restricted during replication but also occurs during transcription, even though the unwinding takes place in a different way. Transcription is a very important step, perhaps the most important step in regulation. Transcription determines which genes will be expressed and, therefore, proceed for decoding and protein synthesis. During the process of transcription, the 3′ → 5′ noncoding DNA strand becomes the template for the synthesis of RNA. The RNA transcript, therefore, keeps the sequence order of the coding strand, 5′ → 3′. The main enzyme here is RNA polymerase. Regulation at this level is very unique and markedly different in prokaryotes and eukaryotes. Therefore, for clarity, I describe transcription in prokaryotes first (this chapter) and continue with transcription in eukaryotes in Chapter 6). The first part of this chapter examines the structure of the prokaryotic RNA polymerase and the mechanisms of transcription initiation and elongation as revealed by 3-D complexes of RNA polymerase and DNA. In the second part, I present some of the mechanisms involved in regulating gene transcription in prokaryotes. Having as a focus to present these events at the 3-D level, my aim is not to be redundant, and in doing so I have omitted information that can be found in microbiology and biochemistry books. Therefore, the basic structural motifs involved in transcriptional regulation are presented in a few regulators to pinpoint similarities and differences.
The mitochondrial permeability transition in ammonia neurotoxicity

Ammonia is a neurotoxin which, in high concentrations (> 1 mM), can result in seizures and death, while stupor and coma occur at lower concentrations.1,2 It is generally accepted that ammonia plays a major role in the pathogenesis of hepatic encephalopathy (HE).3 It is also an important factor in urea cycle defects and other metabolic disorders, including Reye’s syndrome, organic acidurias, valproate toxicity, transient hyperammonemia in infants, and idiopathic hyperammonemia.2,4,5
Markov decision processes with controlled observations and the sensor querying problem

This paper studies a class of discrete-time stochastic control problems with controlled observations. This problem is motivated by the wide deployment of networked control systems and data fusion, where querying all sensors is not possible at each time instant. Since only part of the observation information is available at each time step, the controller has to balance the system performance with the penalty of the requested information (query). We first formulate the problem for a general partially observed Markov decision process model and provide a sufficient condition for existence of ergodic control with hierarchical information structure. Then we specialize to the linear stochastic control problem, where we show that the separation principle partially holds. We also show that distributing sensors does not affect the stability of the system: if the system can be stabilized with all sensor data available at the controller, it can also be stabilized with sensor querying. A sharp condition is provided for the existence of ergodic control for LQG control problem with sensor querying.
A New Kind of Gold? Investments in Housing Under Economic Uncertainty

Since the 1960s, Americans have looked to the stock market for investments. Residential real estate was just a place to live. No more. Much like gold in the 1970s, the purchase of residential real estate now appears to be treated by Americans like the investment of choice in times of economic uncertainty. This paper shows that there are two reasons for this major behavioral change. First, real estate has become the psychological equivalent of gold, the asset considered most tangible and therefore, rationally or not, the safest. Second, the timing of the shift in real estate investment patterns suggests that the change is a side effect of the stimulative monetary policy used during economic recessions. Reduced interest rates encourage investment in real estate by making it more affordable.
Temperature-sensitive mutants for the replication of plasmids in Escherichia coli: requirement for deoxyribonucleic acid polymerase I in the replication of the plasmid ColE 1 .

An Escherichia coli mutant (polA1), defective in deoxyribonucleic acid (DNA) polymerase I, (EC 2.7.7.7) is unable to maintain colicinogenic factor E1 (ColE1), whereas several sex factor plasmids are maintained normally in this strain. polA1 mutant strains containing these sex factor plasmids do not exhibit a readily detectable plasmid-induced polymerase activity. A series of E. coli mutants that are temperature sensitive for ColE1 maintenance, but able to maintain other plasmids, were isolated and shown to fall into two phenotypic groups. Mutants in one group are defective specifically in ColE1 maintenance at 43 C, but exhibit normal DNA polymerase I activity. Mutations in the second group map in the polA gene of E. coli, and bacteria carrying these mutations are sensitive to methylmethanesulfonate (MMS). Revertants that were selected either for MMS resistance or the ability to maintain ColE1 were normal for both properties. The DNA polymerase I enzyme of two of these mutants shows a pronounced temperature sensitivity when compared to the wild-type enzyme. An examination of the role of DNA polymerase I in ColE1 maintenance indicates that it is essential for normal replication of the plasmid. In addition, the presence of a functional DNA polymerase I in both the donor and recipient cell is required for the ColV-promoted conjugal transfer of ColE1 and establishment of the plasmid in the recipient cell.
Uridine diphosphate glucose dehydrogenase of calf liver: Properties and inhibition characteristics with uridine diphosphate xylose analogues☆

Abstract UDP-glucose dehydrogenase of calf liver dissociated in guanidine-HCl into six subunits. The number of reactive sulfhydrylgroups of native and guanidine-HCl-treated enzyme was found to be 20 ± 1 and 46 ± 1, respectively, per mole of native enzyme. A crude preparation of UDP-glucose pyrophosphorylase from yeast was used for the preparation of 5-hydroxyuridine diphosphate xylose and 5-aminouridine diphosphate xylose. 5,6-Dihydrouridine diphosphate xylose was prepared by catalytic reduction of UDP-xylose. The nature of the inhibition produced by UDP-xylose or its analogues was similar with respect to either UDP-glucose or NAD + , the two substrates for the enzyme. Hydrogenation of the 5,6-double bond or substitution of a hydroxyl group at the C-5 position of the pyrimidine portion of UDP-xylose decreased its inhibitory activity. Substitution of an amino group at the C-5 position, however, did not alter the activity of the allosteric inhibitor.
Interferon and Host Resistance to Rauscher Virus-induced Leukemia

Abstract A random bred strain of mice (CD-1) was shown to develop resistance to Rauscher leukemia virus (RLV) as the animals matured. Resistant adult mice developed relatively high-serum levels of interferon (150 to 2,000 units per ml) in contrast to susceptible 21-day-old animals in which interferon levels were undetectable or low (less than 20 to 200 units per ml). A similar correlation between resistance and interferon levels was observed in comparisons between resistant CD-1 and susceptible BALB/c mice. The F1 hybrids of CD-1 × BALB/c and BALB/c × CD-1 matings manifested an intermediate degree of susceptibility and interferon production. The difference in interferon production by CD-1 and BALB/c mice was specific for the RLV-host interaction, since both strains produced equal serum levels of interferon in response to Sindbis and Newcastle disease viruses. The mortality of CD-1 suckling mice infected with Rauscher leukemia virus was decreased by treatment with interferon. These data demonstrate an association between interferon production by the host and the observed relative resistance of the CD-1 strain of adult mice to the subsequent malignant transformation. This virus-host relationship provides an excellent model for further study of factors affecting the development of virus-induced leukemia.
Optically induced shifts in the frequency of the 3 H 4 - 1 D 2 transition of Pr 3+ in LaF 3

Photon-echo techniques were employed to measure the homogeneous dephasing rate of the 592.5-nm, $^{3}$${\mathit{H}}_{4\mathrm{\ensuremath{-}}}^{1}$${\mathit{D}}_{2}$, transition of ${\mathrm{Pr}}^{3+}$ as experimental parameters affecting the number of ${\mathrm{Pr}}^{3+}$ ions optically excited were varied. These parameters include the dopant concentration and the intensity, carrier frequency, and bandwidth of the excitation pulses. Dephasing rates are found to contain a background contribution whose magnitude is dependent upon the specific crystal sample studied and a second contribution whose magnitude increases with the number of ${\mathrm{Pr}}^{3+}$ ions changing state in the course of the echo excitation sequence. The second contribution to the dephasing rate is attributed to the presence of optical instantaneous diffusion, i.e., the redistribution of ionic transition frequencies consequent to optical excitation, in the samples.
Twenty Years of the Commercial Internet, Part 2

This column discusses the effect of the Internet and Web on the US economy from the 1990s to the present.
Lipoprotein associated phospholipase A2 inhibition reduces generation of oxidized fatty acids: Lp-LPA2 reduces oxidized fatty acids.

Purpose Lipoprotein associated phospholipase A2 (Lp-PLA2) is an emerging cardiovascular risk marker. After low-density lipoprotein (LDL) oxidation, Lp-PLA2 generates oxidized nonesterified fatty acids and lysophosphatidylcholine, both of which have demonstrated proinflammatory and proapoptotic activities. Through the use of a selective inhibitor of Lp-PLA2 (SB-677116), we investigated whether Lp-PLA2 participates in the ex vivo generation of oxidized fatty acids (ox-FA).
Immediate surgical outcomes for radical prostatectomy in the University HealthSystem Consortium Clinical Data Base: the impact of hospital case volume, hospital size and geographical region on 48 000 patients

OBJECTIVE To determine the impact of hospital variables on immediate surgical outcomes for patients treated with radical prostatectomy (RP) in academic centres. PATIENTS AND METHODS The University HealthSystem Consortium (UHC) Clinical Data Base was queried for data corresponding to patients who had RP at one of 130 academic medical centres nationwide between 2003 and the second quarter of 2007 (48 086). RP case volume (1–99, 100–499 and >500), total discharges (1–49 999, 50 000–99 999, >100 000), and geographical region (five categories) were determined and categorized for each academic centre. Analysis of variance and the Tukey statistic were used to assess the results. Length of stay (LOS), intensive care unit (ICU) rate, complication rate (CR) and in-hospital mortality (IHM) were analysed. RESULTS Case volume was a significant predictor of LOS, ICU and CR. The mean LOS was 3.77, 2.65 and 2.09 days, respectively, for centres from three tiers of lowest to highest case volumes (P < 0.001). ICU rates for the three tiers were 18.57, 3.61, and 1.30 (P < 0.001); CRs were 15.93, 8.79 and 5.76 (P < 0.001). Tukey analysis showed a ‘ceiling’ effect for ICU and CRs; there were no differences between the two higher case-volume groups. IHM was not significantly different between groups stratified by case volume. Stratification by total discharges showed differences in ICU rates only (P = 0.003). Stratification by geographical region showed no differences in outcome. CONCLUSIONS RP case volume was an important variable in predicting three of the four outcome variables. CRs and ICU rates showed a ‘ceiling effect’ suggesting that an unknown ‘critical volume’ of cases portends improved surgical outcomes.
Astrocytic Hamartoma of the optic disc and multiple café-au-lait macules in a child with neurofibromatosis type 2

Neurofibromatosis type 2 (NF2) is a heritable syndrome characterized by multifocal proliferation of neural crest-derived cells. The characteristic and diagnostic finding of NF2 is bilateral vestibular nerve schwannomas (acoustic neuromas). In addition to other tumors involving the central and peripheral nervous systems, ophthalmic manifestations, including posterior subcapsular and peripheral cortical cataracts, optic nerve meningiomas, epiretinal membrane, and combined pigment epithelial and retinal hamartomas, are common to NF2. Herein we present an 8-year-old girl with NF2 and astrocytic hamartoma of the optic disc. This patient had been previously diagnosed with NF1 on the basis of multiple CAL macules and suspected subcutaneous neurofibromas. However, neuroimaging revealed bilateral acoustic neuromas, leading to a clinical diagnosis of NF2. Subsequent molecular genetic analysis confirmed the NF2 diagnosis. Multiple CAL macules and astrocytic hamartomas, while associated with NF1, are rarely associated with NF2. Specifically, we are not aware of any reported cases of optic disc astrocytic hamartoma in the setting of NF2.
Resource Mobilization and Survival Tactics of Poverty Advocacy Groups

One of the ongoing problems with democratic systems concerns who has a voice in decision-making. The least affluent members in society seldom are heard, even though they may have quite a number of grievances. Instead, the popular press is filled with accounts of interest groups gaining inordinate favor from elected officials. For example, as details of the Savings and Loan debacle are uncovered, they reveal intricate relationships between powerful special interests and lawmakers.
Evaluating multiprocessor performance: an exercise in metamodeling:

This paper points to the viability of metamodels in performance evaluation. A metamodel, in the sense it is used here, is a simple mathematical expression that describes a performance measure in terms of the system parameters, and is derived from experi ments with a simulation model of the system. The system con sidered is a bus-sufficient multiprocessor, and the performance measure under focus is its processing efficiency. The process of metamodel development is illustrated to show that a reliable metamodel can be derived with relative ease. It is also argued that with sufficient care taken in selecting the form of the meta model, it may be justifiable to use the metamodel beyond the experimental domain over which it is developed. Specifically, a metamodel is proposed for the processing efficiency of a multi processor system. It is shown to be a reasonably good approxima tion to the simulation model, and by extension, to the original system.
Mathematical analysis in psychology of education: Computation of stimulation, rapport, and instructor's driving power

Mathematical expressions are derived for such concepts as stimulation of student by instructor, student-instructor rapport, and driving power of instructor, in terms of the student's and the instructor's foci of attention, their strength of concentration, and the intensity of the presentation and of the reception of details of subject matter. Under the assumption of normal distribution, the mathematical methods of combination and integration yield conclusions on summary integral effects of interrelations within the educational team. The psychological interpretation of the mathematical results thus obtained conforms with common sense. The main emphasis of the article is the exposition of how the mathematical method of combination and integration can be used to estimate the resultant effect of various independent combined simple factors acting independently within the individuals forming the educational team. No claim is made as to the absolute truthfulness and reliability of the psychological postulates used at the beginning stage of the mathematical analysis.
SPECTRO-ASTROMETRY OF WATER IN DR TAURI

We present high-resolution, near-infrared spectro-astrometric (SA) data for the T Tauri star DR Tau using NIRSPEC at the Keck II telescope. Spectro-astrometry obtains sub-seeing spatial information from emission lines originating in a non-point source object, such as a circumstellar disk. We report the first detection of water SA signatures in a protoplanetary disk. Three water features near 3 μm were averaged together to produce the total signal analyzed. Using a disk model, we constrained the position angle of the disk (~140°), the inclination of the disk (~13°), and the emitting region of the emission lines (~0.056-0.38 AU).
Influence of thrombus components in mediating Staphylococcus aureus adhesion to polyurethane surfaces

The role of protein and cellular components of thrombi in mediating bacterial adhesion on artificial surfaces was investigated in this study. The attachment of Staphylococcus aureus on polyurethane surfaces was observed directly using an automated video microscopy system. Surfaces were preconditioned with components of platelet-fibrin thrombi, including fibrinogen, thrombin, plasma, and isolated platelets. Experiments were performed in a radial flow chamber, and attachment rate constants were compared on the preconditioned surfaces in an effort to understand the complex relationship that exists between bacterial infection and thrombosis on synthetic biomaterials. Preadsorption of fibrinogen to surfaces significantly increased S. aureus adhesion compared to those preadsorbed with albumin alone while the presence of fibrin dramatically increased bacterial attachment compared to plasma preadsorbed surfaces. While the presence of adherent platelets also increased bacterial attachment, fibrin appeared to play a larger role in mediating bacterial adhesion on polyurethane surfaces. Striking results were obtained on the zwitterionic phosphonated polyurethane for a number of pretreatment conditions with regard to decreased bacterial adhesion and fibrinogen deposition.
Analysis of transients in nonuniform and uniform multiconductor transmission lines

The author presents an effective method for computation of the transient response of multiple nonuniform transmission lines. This time-domain analysis technique can predict reflections and crosstalk. The proposed spectral technique is used to transform partial differential equations describing a system of transmission lines into a set of linear ordinary differential equations, which can be solved with one of the many well-developed integration techniques. Numerical experiments performed with the prototype program showed that the method can solve specific problems (lossless, uniform lines) just as fast as less general methods based on modal analysis exploiting the particular properties of lines. >
Cyclotron programs for a small computer

A brief functional description of the various MSU cyclotron computer programs is given. The routines should be particularly useful as a guide for construction of similar programs for institutions with small computers.
Fabrication, optical transmittance, and hardness of IR-transparent ceramics made from nanophase yttria

Abstract Commercially available nanophase yttria powder was used to fabricate a transparent ceramic and its optical transmittance and hardness were measured. The nanophase yttria powder was dry-pressed without the use of any binders. Subsequently, the green body was sintered in air, hot-isostatically pressed, and polished, resulting in an IR-transparent ceramic. Scanning electron microscopy revealed a grain size of 21.5 ± 11.1 μm. Optical transmittance reached about 60% at 1 μm, and hardness measurements showed 792 HK 100 g , 704 HK 500 g , and 767 HV 100 g .
Spectral sensitivity of the modulation-sensitive mechanism of vision

Abstract Spectral sensitivities were measured by a procedure of flicker threshold. The shape of the spectral sensitivity curve depends systematically on both the frequency and percentage of temporal modulation. The variations in spectral sensitivity are consistent with two different sets of deLange characteristics, one set applicable to short and medium wavelengths, the second applicable to long wavelengths.