cssi/SciSciGPT-SciSciNet huggingface dataset:
Criteria for Emergency Brain MRI During Stroke-Alert.

Abstract Objectives Intravenous (IV) tissue plasminogen activator (tPA) should be given to patients with acute ischemic stroke (AIS) and avoided in stroke mimics (SM). Select use of emergency brain magnetic resonance imaging (eMRI-brain) in stroke-alerts aids diagnosis, but accepted utilization criteria for eMRI-brain do not currently exist. We developed criteria for eMRI-brain and report the yield of eMRI-brain in stroke-alert patients. Materials and Methods We developed three history-based criteria for performing eMRI-brain during stroke-alerts: (1) history of previous similar deficits, (2) change in consciousness at onset of symptoms, (3) symptom presentation consistent with migraine aura. We then performed a retrospective chart review of patients who presented as a stroke-alert over a 5-year period and determined how these criteria affected administration of IV tPA to AIS and SM patients. Results Among 3,512 stroke-alerts, 230 (8.1%) patients met our criteria for eMRI-brain exams: 217 (92.6%) had SM and 17 (7.4%) had AIS. Our IV tPA decision-making analysis showed that based on eMRI-brain IV tPA was less frequently administered to SM patients (PCC-0.841, p=0.036) with less failures to administer IV tPA to patients with AIS (PCC -0.907, p-value=0.013, Pearson correlation coefficient). No patients became ineligible for IV tPA due to MRI-related time delays. Conclusions Our history based criteria for performing eMRI-brain during stroke-alerts show a high yield of stroke mimics. Selective eMRI-brain improves decision-making accuracy regarding IV tPA administration.
Academic Medicine Faculty Perceptions of Work-Life Balance Before and Since the COVID-19 Pandemic.

Importance: How the COVID-19 pandemic has affected academic medicine faculty's work-life balance is unknown. Objective: To assess the association of perceived work-life conflict with academic medicine faculty intention to leave, reducing employment to part time, or declining leadership opportunities before and since the COVID-19 pandemic. Design, Settings, and Participants: An anonymous online survey of medical, graduate, and health professions school faculty was conducted at a single large, urban academic medical center between September 1 and September 25, 2020. Main Outcomes and Measures: Self-assessed intention to leave, reducing employment to part time, or turning down leadership opportunities because of work-life conflict before and since the COVID-19 pandemic. Results: Of the 1186 of 3088 (38%) of faculty members who answered the survey, 649 (55%) were women and 682 (58%) were White individuals. Respondents were representative of the overall faculty demographic characteristics except for an overrepresentation of female faculty respondents and underrepresentation of Asian faculty respondents compared with all faculty (female faculty: 649 [55%] vs 1368 [44%]; Asian faculty: 259 [22%] vs 963 [31%]). After the start of the COVID-19 pandemic, faculty were more likely to consider leaving or reducing employment to part time compared with before the pandemic (leaving: 225 [23%] vs 133 [14%]; P < .001; reduce hours: 281 [29%] vs 206 [22%]; P < .001). Women were more likely than men to reduce employment to part time before the COVID-19 pandemic (153 [28%] vs 44 [12%]; P < .001) and to consider both leaving or reducing employment to part time since the COVID-19 pandemic (leaving: 154 [28%] vs 56 [15%]; P < .001; reduce employment: 215 [40%] vs 49 [13%]; P < .001). Faculty with children were more likely to consider leaving and reducing employment since the COVID-19 pandemic compared with before the pandemic (leaving: 159 [29%] vs 93 [17%]; P < .001; reduce employment: 213 [40%] vs 130 [24%]; P < .001). Women with children compared with women without children were also more likely to consider leaving since the COVID-19 pandemic than before (113 [35%] vs 39 [17%]; P < .001). Working parent faculty and women were more likely to decline leadership opportunities both before (faculty with children vs without children: 297 [32%] vs 84 [9%]; P < .001; women vs men: 206 [29%] vs 47 [13%]; P < .001) and since the COVID-19 pandemic (faculty with children vs faculty without children: 316 [34%] vs 93 [10 %]; P < .001; women vs men: 148 [28%] vs 51 [14%]; P < .001). Conclusions and Relevance: In this survey study, the perceived stressors associated with work-life integration were higher in women than men, were highest in women with children, and have been exacerbated by the COVID-19 pandemic. The association of both gender and parenting with increased perceived work-life stress may disproportionately decrease the long-term retention and promotion of junior and midcareer women faculty.
Am I Really Qualified To Be Here: Exploring The Impact Of Impostor Phenomenon On Training And Careers In OB/GYN Medical Education.

OBJECTIVE Individuals with Impostor Phenomenon (IP) believe they have achieved success by fooling others into thinking they are intelligent/capable and fear they will be discovered. This fear has been shown to cause psychological distress and may affect OB/GYN training. The objective of this study was to investigate the prevalence of IP and correlation with anxiety among OB/GYN trainees and faculty. DESIGN/SETTING An anonymous cross-sectional survey including a demographic questioner, Clance Impostor Scale, and Generalized Anxiety Disorder 2-items screening tool was distributed to 200 attendees at the 2019 American College of Obstetricians and Gynecologists Annual Meeting. PARTICIPANTS Eighty-nine medical students, 38 residents, 3 fellows, and 9 attendings completed the survey for a response rate of 72%. RESULTS The average participant experienced frequent feelings of IP with the mean score of 65 ± 18. Nine (8%) experienced few feelings of IP, 27 (24%) had moderate IP feelings, 55 (50%) had frequent IP feelings, and 20 (18%) had intense IP feeling. There was no difference between IP score and trainee/faculty gender, race, or region of country. The degree of IP was significantly associated with level of medical training with more experienced physicians scoring lower than trainees (F = 6.07, p = 0.001). Finally, an association was found between anxiety and IP; individuals with a positive GAD-2 screen had significantly more feelings of IP compared to individuals with a negative GAD-2 screen (t = 4/79, p CONCLUSION This study suggests that IP is likely prevalent among OB/GYN trainees and correlate with anxiety. Further discussion is needed regarding the impact of IP on medical education training and career advancement in the field of OB/GYN and other surgical specialties.
The maximum entropy distributions of collisionless particle velocity, speed, and energy for statistical mechanics of self-gravitating collisionless flow (SG-CFD)

The halo-mediated inverse mass cascade is a key feature of the intermediate statistically steady state for self-gravitating collisionless flow (SG-CFD). How the inverse mass cascade maximizes system entropy and develops limiting velocity/energy distributions are fundamental questions to answer. We present a statistical theory concerning the maximum entropy distributions of particle velocity, speed, and energy for self-gravitating systems involving a power-law long-range interaction with an arbitrary exponent $n$. For system with long-range interaction ($-2<n<0$), a broad spectrum of halos and halo groups are necessary to form from inverse mass cascade to maximize the system entropy. While particle velocity in each halo group is still Gaussian, the velocity distribution of entire system can be non-Gaussian. With the virial equilibrium for local mechanical equilibrium of halo groups, the maximum entropy principle is applied for statistical equilibrium of global system to derive the limiting distributions. Halo mass function is not required in this formulation, but it is a direct result of entropy maximization. The predicted velocity distribution involves a shape parameter $\alpha$ that is dependent on the exponent $n$. The velocity distribution approaches Laplacian with $\alpha\rightarrow0$ and Gaussian with $\alpha\rightarrow\infty$. For intermediate $\alpha$, the maximum entropy distribution naturally exhibits a Gaussian core at small velocity and exponential wings at large velocity. The total energy of collisionless particles at a given speed follows a parabolic scaling for small speed ($\epsilon \propto v^2$) and a linear scaling ($\epsilon \propto v$) for large speed. Results are compared against a N-body simulation with good agreement.
Inter-storm variation in microplastic concentration and polymer type at stormwater outfalls and a bioretention basin

Abstract Microplastics (MP) are a commonly reported pollutant in the freshwater, marine, and soil environment. Few studies to date have reported MP concentrations and polymer types observed in stormwater, particularly not for catchments with separate storm sewers. The objectives of this study were to determine the microplastic concentration, polymer fingerprints, and the inter-storm variation of MP in two stormwater outfalls and a bioretention basin. Composite stormwater samples were collected at each site across three rain events each in catchments with urban and suburban land use. Particles 250 to 2000 μm were collected, separated into two sizes classes, treated with a wet peroxide oxidation, density separated with NaCl, and buoyant particles (fragments, films, and spheres) were collected for analysis with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Significant differences were observed in the total polymer concentrations and profiles between the sampling sites, potentially due to differences in land use within the catchments sampled, but not between size classes. The highest MP concentrations were observed in samples from the bioretention basin compared to the stormwater outfalls sampled, indicating the potential for green infrastructure to capture MP in the size range studied here. A weak but significant negative correlation was observed between cumulative rainfall (1.5 to 4.5 cm) and MP concentrations but no correlation was observed between antecedent dry days and MP concentrations. These data represent a conservative measure of MP concentrations given that fibers, particles 1.2 g/mL) were not targeted, but all targeted particles were analyzed with ATR-FTIR. Overall, these results presented provide insight into the loading and character (size, morphology, polymer type) of buoyant MP particles in stormwater that may be useful in designing mitigation strategies.
Robust atlas-based segmentation of highly variable anatomy: left atrium segmentation

Automatic segmentation of the heart's left atrium offers great benefits for planning and outcome evaluation of atrial ablation procedures. However, the high anatomical variability of the left atrium presents significant challenges for atlas-guided segmentation. In this paper, we demonstrate an automatic method for left atrium segmentation using weighted voting label fusion and a variant of the demons registration algorithm adapted to handle images with different intensity distributions. We achieve accurate automatic segmentation that is robust to the high anatomical variations in the shape of the left atrium in a clinical dataset of MRA images.
Embracing uncertainty: the new machine intelligence

Many of the early applications of machine intelligence were based on expert systems constructed using rules elicited from human experts. Limitations in the applicability of this approach helped to drive black-box statistical methods, such as neural networks, based on learning from data. These black-box methods too are hitting limitations, due to the challenges of incorporating background knowledge. In this talk I will describe a new paradigm for machine intelligence which has emerged over the last five years, and which allows prior knowledge from domain experts to be integrated with machine learning techniques to enable a new generation of large-scale applications. The talk will be illustrated with tutorial examples as well as real-world case studies.
CONTROL OF ASPARTATE TRANSCARBAMYLASE ACTIVITY IN TYPE 5 ADENOVIRUS-INFECTED HELA CELLS

Consigli, Richard A. (University of Pennsylvania, Philadelphia), and Harold S. Ginsberg. Control of aspartate transcarbamylase activity in type 5 adenovirus-infected HeLa cells. J. Bacteriol. 87:1027–1033. 1964.—Type 5 adenovirus infection induces increased aspartate transcarbamylase (ATCase) activity during the period of magnified nucleic acid biosynthesis. Increased activity can be prevented by addition of pyrimidines to the culture medium. ATCase in HeLa cells is regulated by feedback inhibition, and purified enzyme can be inhibited in vitro by cytidine triphosphate (CTP). The enzyme from infected cells has a pH optimum, maximal velocity, and Km for aspartate distinctly different from ATCase from control cells. However, heating of ATCase from uninfected cells converts the enzyme so that its characteristics are identical with enzyme from infected cells. Conversely, addition of CTP to ATCase from infected cells changes the characteristics of the enzyme so that they are the same as those of enzyme from uninfected cells. The evidence presented suggests that increased nucleic acid biosynthesis in infected cells initiates a release from feedback inhibition and increases ATCase activity by reducing the concentration of pyrimidines and purines in the acid-soluble pool.
Active frame selection for label propagation in videos

Manually segmenting and labeling objects in video sequences is quite tedious, yet such annotations are valuable for learning-based approaches to object and activity recognition. While automatic label propagation can help, existing methods simply propagate annotations from arbitrarily selected frames (e.g., the first one) and so may fail to best leverage the human effort invested. We define an active frame selection problem: select k frames for manual labeling, such that automatic pixel-level label propagation can proceed with minimal expected error. We propose a solution that directly ties a joint frame selection criterion to the predicted errors of a flow-based random field propagation model. It selects the set of k frames that together minimize the total mislabeling risk over the entire sequence. We derive an efficient dynamic programming solution to optimize the criterion. Further, we show how to automatically determine how many total frames k should be labeled in order to minimize the total manual effort spent labeling and correcting propagation errors. We demonstrate our method's clear advantages over several baselines, saving hours of human effort per video.
Designing secure and reliable wireless sensor networks under a pairwise key predistribution scheme

We investigate k-connectivity in secure wireless sensor networks under the random pairwise key predistribution scheme with unreliable links; a network is said to be k-connected if it remains connected despite the failure of any of its (k − 1) nodes or links. With wireless communication links modeled as independent on-off channels, this amounts to analyzing a random graph model formed by intersecting a random K-out graph and an Erdős-Renyi graph. We present conditions on how to scale the parameters of this intersection model so that the resulting graph is k-connected with probability approaching to one (resp. zero) as the number of nodes gets large. The resulting zero-one law is shown to improve and sharpen the previous result on the 1-connectivity of the same model. We also provide numerical results to support our analysis and show that even in the finite node regime, our results can provide useful guidelines for designing sensor networks that are secure and reliable.
Noise and dynamics of stimulated-Brillouin-scattering microresonator lasers

We use theoretical analysis and numerical simulation to investigate the operation of a laser oscillating from gain supplied by stimulated Brillouin scattering (SBS) in a microresonator. The interaction of the forward, backward, and density waves within the microresonator results in a set of coupled-mode equations describing both the laser's phase and amplitude evolution over time. Using this coupled-mode formalism, we investigate the performance of the SBS laser under noise perturbation and identify the fundamental parameters and their optimization to enable low-noise SBS operation. The intrinsic laser linewidth, which is primarily limited by incoherent thermal occupation of the density wave, can be of order hertz or below. Our analysis also determines the SBS laser's relaxation oscillation, which results from the coupling between the optical and density waves, and appears as a resonance in both the phase and amplitude quadratures. We further explore contributions of the pump noise to the SBS laser's performance, which we find under most circumstances to increase the SBS laser noise beyond its fundamental limits. By tightly stabilizing the pump laser onto the microcavity resonance, the transfer of pump noise is significantly reduced. Our analysis is both supported and extended through numerical simulations of the SBS laser.
Opacity of Singly Ionized Helium from Very Tenuous Intergalactic Absorbing Gas

The He II Gunn-Peterson test has been successfully carried out to detect the intergalactic medium (IGM). Jakobsen et al. (1994) reported a flux cutoff shortward of redshifted He II Lyα: emission in the HST prism spectrum of the quasar 0302–003 (z = 3.286), with the optical depth -1.0 +∞ . The spectrum of quasar HS1700+64 (z = 2.743) recently obtained with the Hopkins Ultraviolet Telescope (HUT) reveals a flux depression due to He II absorption (Davidsen, Kriss, & Zheng 1996), with an average optical depth of τ = 1.0±0.07. The findings confirm the Gunn-Peterson absorption produced by primordial helium in the IGM.
Partial purification and characterization of the lck protein-tyrosine kinase from bovine thymus.

Soluble extracts prepared from bovine thymus contain an angiotensin-I-phosphorylating activity that is activated several-fold by high concentrations of NaCl. Fractionation of this protein-tyrosine kinase activity by chromatography on DEAE-cellulose yields a major diffuse peak of activity. The enzymes responsible for this activity are found at much higher levels in extracts from bovine thymus than from bovine spleen. The peak of activity from the DEAE-cellulose column can be further separated into two major peaks by chromatography on heparin-agarose. The second peak to elute from the heparin-agarose column was previously purified through several chromatographic steps to yield a 40 kDa protein-tyrosine kinase (p40). We have now partially purified the early-eluting peak of kinase activity by chromatography on columns of butyl-agarose, protamine-agarose and Sephacryl S200. The enzyme was identified following covalent modification with 5′-fluorosulphonylbenzoyladenosine (FSBA) by reactivity with anti-FSBA antibodies. This procedure labelled a series of 52-56 kDa proteins. These proteins were also recognized by polyclonal anti-peptide antibodies raised against the C-terminal 33 amino acids of p56lck, a major T lymphocyte protein-tyrosine kinase. Peptide maps of the partially purified enzyme were identical to maps generated from p56lck obtained from LSTRA cells. These data suggest that bovine thymus p56lck is responsible for the activity found in the early-eluting peak from heparin-agarose. Antibodies raised against a peptide corresponding to amino acids 39-64 of p56lck, a sequence found near the N-terminus, recognized the slower-migrating, but not the faster-migrating, form of the enzyme, indicating that a fraction of the protein had been proteolysed near the N-terminus during purification. The partially purified bovine enzyme exhibited a restricted substrate specificity in vitro and did not readily phosphorylate human erythrocyte band 3, casein or histone, but was able to phosphorylate acid-treated enolase. The dilute enzyme present in fractions eluting from chromatography columns was unable to catalyse an autophosphorylation reaction. Autophosphorylation could be detected in more concentrated enzyme samples and was readily observed in immune-complex assays. The phosphorylation of angiotensin I by bovine thymus p56lck was weakly activated by polyionic compounds such as heparin and polylysine, and was strongly activated by high concentrations of NaCl.
Cerebral Hyperperfusion and Vasodilatory Changes in Acute Seizure - Report of Three Cases (P6.193)

Objective: To describe seizure induced acute changes in CT perfusion (CTP) and CT angiography (CTA) Background: Multimodal imaging with CT is the prevalent practice to image acute stroke. Seizure is a well-known stroke mimic, perhaps best distinguished from acute ischemic stroke with MRI. Close attention to CTP and CTA may help diagnose acute seizure and avoid unnecessary thrombolysis and its risks. Increased metabolism in seizure is thought to be responsible for increased perfusion. Alternatively, some consider decreased perfusion from neurotransmitter depletion, transient anoxia and spreading depression. Here, we describe the pattern of focal cerebral hyperperfusion with normal head CT and corresponding CTA changes. Materials/ Methods: Three patients presented to ED with the diagnosis of acute stroke, and underwent multimodal stroke imaging with CT head, CTP and CTA. Post processing of perfusion and angiography data was done. Color maps of cerebral blood flow (CBF), volume (CBV), mean transit time (MTT) and time to peak (TTP) map were generated. Qualitative analysis of data was performed. Results: All patients demonstrated normal head CT. No vascular occlusion identified on CTA. CTP demonstrated increased CBF, CBV and decreased MTT, TTP in right frontal lobe in first; left frontal lobe in second; basal ganglia, frontal and temporal lobe in third case. Close attention to CTA demonstrated increased vascularity as dilated cortical branches. The pattern of increased perfusion did not confine to any particular arterial territory in 2 cases. All of them found to have acute seizure of different etiology with no h/o epilepsy. Conclusion: Acute seizure can induce changes in cerebral perfusion and is essential to recognize these changes to distinguish seizure as stroke mimic. Our experience shows cerebral hyperperfusion and seems to correlate with the hypermetabolic profile of seizure focus. Enlarged caliber of cortical vessels in the areas of hyperperfusion should alert for acute seizure induced changes. The vasodilatory changes of the cortical branches near seizure focus have never been reported. Study Supported by: none Disclosure: Dr. Krishnaiah has nothing to disclose. Dr. Said Said has nothing to disclose. Dr. Thamburaj has nothing to disclose.
Secret Consumer Scores and Segmentations: Separating Consumer 'Haves' from 'Have-Nots'

“Big Data” is big business. Data brokers profit by tracking consumers’ information and behavior both on- and offline and using this collected data to assign consumers evaluative scores and classify consumers into segments. Companies then use these consumer scores and segmentations for marketing and to determine what deals, offers, and remedies they provide to different individuals. These valuations and classifications are based on not only consumers’ financial histories and relevant interests, but also their race, gender, ZIP Code, social status, education, familial ties, and a wide range of additional data. Nonetheless, consumers are largely unaware of these scores and segmentations, and generally have no way to challenge their veracity because they usually fall outside the purview of the Fair Credit Reporting Act (FCRA). Moreover, companies’ use of these data devices may foster discrimination and augment preexisting power imbalances among consumers by funneling the best deals and remedies to the wealthiest and most sophisticated consumers. Use of these scores and segmentations increases the growing gap between powerful “haves” and vulnerable “have-nots.” This Article sheds light on these data devices and aims to spark adoption of data privacy regulations that protect all consumers regardless of their educational, economic, ethnic, or social status.
Penicillin skin testing in the evaluation and management of penicillin allergy.

Objective To review the role of penicillin skin testing in the evaluation and management of penicillin allergy mediated by IgE. Data Sources PubMed and OVID search of English-language articles regarding penicillin allergy, penicillin allergy testing, and management of penicillin allergy. Study Selection Articles pertinent to the subject matter were selected and reviewed. Results The major determinant (benzylpenicillin polylysine) detects the greatest number of penicillin allergic patients during skin testing, and the minor determinants of penicillin increase the sensitivity of penicillin skin testing. Penicillin skin testing to the major and minor determinants was found to have a negative predictive value of 97% to 99%. The incidence of systemic adverse reaction to penicillin skin testing is less than 1%. Conclusion A detailed history of the prior reaction to penicillin is an integral part of the evaluation, but it is not accurate in predicting a positive penicillin skin test result. A patient with a negative penicillin skin test result to the major and minor determinants is at a low risk of an immediate-type hypersensitivity reaction to penicillin. Patients with a positive skin test result should undergo desensitization to penicillin or an alternative antibiotic should be considered.
X-Rays from Visible Aurorae at Minneapolis

During three auroral storms on June 30-July 1, September 12-13, and September 22-23, 1957, we have observed bursts of x-rays during balloon flights at 10 g/${\mathrm{cm}}^{2}$ depth in the atmosphere over Minneapolis. The x-rays have an energy of from 50 to 100 kev, an integrated intensity from 0.03 to 0.14 mr, and a maximum measured peak intensity of 0.4 mr/hr. One burst was observed at 47 g/${\mathrm{cm}}^{2}$ atmospheric depth (70 000 ft), and we estimate that above the atmosphere this may have corresponded to 500 mr/hr for at least 10 minutes. The current of high-energy electrons is at least 3\ifmmode\times\else\texttimes\fi{}${10}^{6}$ electrons/${\mathrm{cm}}^{2}$ sec, and probably an order of magnitude greater, and is therefore approximately equal to auroral proton fluxes, and to the fluxes observed in soft radiation at rocket heights. The x-ray bursts usually appear when a homogeneous auroral arc develops a strong ray structure, or when rays increase in intensity. The inferred energy and high velocity of the primary auroral electrons necessitates an acceleration mechanism near the earth to avoid contradictions with the commonly accepted sun-earth transit times for corpuscular beams.
Domestic Violence, Refugee Flows, and International Tension: The Case of EI Salvador

When viewed as a political problem rather than as a humanitarian or legal issue, refugee flows present many potential challenges to state pQlicy-makers. Challenges to decision-making autonomy are among the most significant of these. Such challenges arise because of the ability of refugee flows to exacerbate international tensions and contribute to increased levels of domestic violence. They pose an especially severe problem where political development is weak and the expansion of state autonomy isa critical issue for policy-makers. In states that are hostile to one another, it is obvious that refugee flows are likely to take on a political rather than humanitarian dimension. The receiving state will at the very least use the refugees for propaganda purposes. It might be expected that when the sending and receiving states are friendly or at least ideologically compatible, any response to refugees will be humanitarian in nature. However, where the cause of the refugee flow is domestic repression and violence, the response to the flow is likely to be politicized. The tensions acccompanying refugee flows can be organized around the issue of decision-making autonomy. By far those tensions surround ing foreign policy options present the greatest potential for creating and exacerbat ing regional tension, because they most directly involve the refugee in the power calculations made by states regarding their ability to realize national security ob jectives. In states where decision-making autonomy is weak, policy-makers react to challenges to their authority by evoking national security whenever possible. By emphasizing threats to security, they can unite elite groups and justify repressive solutions to problems. Refugees fleeing repression in a neighbouring state present challenges to decision-making autonomy and potentially threaten national security in the receiving state. To the extent that policy-makers in the receiving state have developed a habit of geopolitical thinking, they are likely to respond to the refugees primarily as a threat to national security. The most m mediate victims are the refugees themselves, but the potential is created for in creased regional violence. This phenomenon is illustrated by the flow of refugees from El Salvador into Honduras. Language: en
Limits on stability of positive molecular ions

It is shown that a positive diatomic molecule consisting of N electrons and two nuclei with charges Z1 and Z2 is unstable with respect to breakup into two atomic subsystems if the nuclear charges are sufficiently large. Bounds on the critical charge are obtained in the limit as N → ∞.
Mathematical control theory solution of an interactive accounting flows model

In this paper we have applied the mathematical control theory to the accounting network flows, where the flow rates are constrained by linear inequalities. The optimal control policy is of the “generalized bang-bang” variety which is obtained by solving at each instant in time a linear programming problem whose objective function parameters are determined by the “switching function” which is derived from the Hamiltonian function. The interpretation of the adjoint variables of the control problem and the dual evaluators of the linear programming problem demonstrates an interesting interaction of the cross section phase of the problem, which is characterized by linear programming, and the dynamic phase of the problem, which is characterized by control theory.
The evolving role of axillary lymph node dissection in the modern era of breast cancer management

The standard of practice in breast cancer surgery is that all patients with a positive sentinel node mandate an axillary lymph node dissection (ALND). Recently, this dogma has been challenged by a trial from ACOSOG (American College Of Surgeons Oncology Group) (Trial Z0011) which demonstrated that patients (without clinically/radiologically apparent axillary metastases) undergoing breast conserving surgery (i.e lumpectomy followed by whole breast radiotherapy) with positive sentinel nodes failed to derive any significant benefit by having an axillary lymph node dissection (ALND) [2]. The logical progression from this study is to question the validity of performing routine axillary lymph node dissections on all patients with positive sentinel lymph nodes (SLN). In addition to the Z0011 trial, there is emerging data that additional patients exist who fail to derive any benefit from axillary surgery. The aim of this article is to discuss the potential subpopulations of patients that may avoid unnecessary ALND in the modern era of breast cancer management.
Nuclear medicine in pediatric orthopedics.

In this presentation, the common clinical pediatric problems (appendicular growth aberrations, hip pain, back pain, some aspects of trauma, and inflammatory and infectious processes that can be addressed by nuclear imaging will be discussed. The accurate interpretation of bone scintigraphy in the evaluation of pediatric orthopedic conditions depends on the use of appropriate radiopharmaceuticals and imaging techniques specific for the pediatric population, a knowledge of physiologic changes in the growing skeleton, as well as the different disease processes peculiar to aach age bracket. The physes (growth-plates) will be discussed in detail because they are the most active portion of the pediatric skeleton. Their activity (potential for growth) can be altered by physiologic, developmental aberrations (varus and valgus) and pathologic conditions (trauma, infection, ect.).
Morphology of the human vertebral endplate.

It is presumed that poor intervertebral disc cell nutrition is a contributing factor in degeneration, and is exacerbated by vertebral endplate sclerosis. Yet, quantitative relationships between endplate morphology and degeneration are unavailable. We investigated how endplate bone microstructure relates to indices of disc degeneration, such as morphologic grade, proteoglycan content, and cell density. Intervertebral core samples [n = 96, 14 subjects, L1–L5 level, ages 35–85 (64 ± 16 years), degeneration grade 1 (n = 4), grade 2 (n = 32), grade 3 (n = 44), grade 4 (n = 10), grade 5 (n = 6)] that included subchondral bone, cartilage endplate, and adjacent nucleus were harvested from human cadaveric lumbar spines. The morphology of the vertebral endplate was analyzed using µCT and the adjacent nucleus tissue was collected for biochemical and cellular analyses. Relationships between vertebral endplate morphology and adjacent disc degeneration were analyzed. Contrary to the prevailing notion, vertebral endplate porosity increased between 50% and 130% and trabecular thickness decreased by between 20% and 50% with advancing disc degeneration (p < 0.05). We also observed that nucleus cell density increased (R2 = 0.33, p < 0.05) and proteoglycan content decreased (R2 = 0.47, p < 0.05) as the endplate became more porous. Our data suggest that endplate sclerosis is not a fundamental factor contributing to disc degeneration. Rather, the opposite was observed in our samples, as the endplate became progressively more porous with age and degeneration. Since ischemic disc cell behavior is commonly associated with degenerative change, this may be related to other factors such as the quality of vertebral capillaries, as opposed to decreased permeability of intervening tissues. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:280–287, 2012
The Teaching Pyramid: A Model for the Implementation of Classroom Practices Within a Program-Wide Approach to Behavior Support

The Teaching Pyramid (Fox, Dunlap, Hemmeter, Joseph, & Strain, 2003) is a framework for organizing evidence-based practices for promoting social-emotional development and preventing and addressing challenging behavior in preschool programs. In this article, we briefly describe the Teaching Pyramid as a framework for implementing effective practices in the context of a program-wide approach to behavior support. We describe a set of training materials and a fidelity measurement tool and discuss how they may be used to support teachers in implementing new instructional approaches with fidelity. Finally, we discuss other supports that teachers will need to implement the Teaching Pyramid practices and future research that is needed in this area.
Author retrospective for cooperative cache partitioning for chip multiprocessors

In this paper, we reflect on our experiences and the lessons learned in designing and evaluating the cooperative cache partitioning technique for chip multiprocessors.
Do ethnicity and gender moderate the influence of posttraumatic stress disorder on time to smoking lapse

Abstract Background Following a smoking cessation attempt, smokers with posttraumatic stress disorder (PTSD) experience smoking relapse at a higher and faster rate. Black ethnicity and female gender are also associated with lower success rates following smoking cessation. No study to date has prospectively examined how ethnicity and gender may moderate the effect of PTSD on smoking relapse. It was hypothesized that female gender and Black ethnicity would significantly predict early lapse after quitting; further, it was predicted that ethnicity and gender would moderate the effect of PTSD on relapse rate. Methods Smokers with PTSD (n = 48) and without PTSD (n = 56) completed ecological momentary assessment (EMA) the week after a quit date, and self-initiated EMA entries after smoking lapse. Smoking abstinence was biologically verified. The sample included Black (62%) and White (38%) participants, and was 50% female. Study hypotheses were tested with Cox proportional hazards regression modeling time to first smoking lapse. Results Study results confirmed the main hypothesis, with a significant PTSD × Ethnicity interaction emerging. The effect of PTSD on smoking relapse was significant for White participants but not for Black participants. No significant gender moderation was found. Conclusion Taken together, study results support previous research, and suggest that the relationship between smoking and PTSD is stronger for White smokers than for minorities. This study has significant implications for research in smoking and mental disease, as well as for smoking cessation treatments for Black smokers.
An extended quadrature-based moment method with log-normal kernel density functions

Abstract An extended quadrature method of moments (EQMOM) with log-normal kernel density functions is developed in this work, and applied to the solution of a population balance equation (PBE) for aggregation and breakup, coalescence, and condensation problems. The cases with one and two kernel density functions are studied analytically, and the existence of an analytical solution is shown. A numerical procedure based on the work of Yuan et al. (2012) is adopted to address cases with a larger number of kernel density functions. Results for the reconstructed number density function (NDF), the time evolution of the zero-order moment and of the mean particle size are compared with those obtained from the rigorous solution of the PBE reported by Vanni (2000) for the cases of aggregation and breakup. A problem concerning coalescence and one regarding condensation, both with analytical solution, are also examined. The results obtained with the proposed approach are compared to those provided by EQMOM with gamma kernel densities. Satisfactory results were obtained for the reconstructed distribution. Excellent agreement was observed between the rigorous solution and the approximated one for the time evolution of the total number density and the mean particle size.
Identification of candidate Purkinje cell-specific markers by gene expression profiling in wild-type and pcd3J mice

Abstract The identification of mRNAs that have restricted expression patterns in the brain represents powerful tools with which to characterize and manipulate the nervous system. Here, we describe a strategy using microarray technology (Affymetrix Mouse Genome 430 2.0 Arrays) to identify mRNA transcripts that are candidate markers of cerebellar Purkinje neurons. Initially, gene expression profiles were compared between cerebella of 4-month-old Purkinje cell degeneration (pcd3J) mice, in which most Purkinje cells had already degenerated and wild-type littermates with a normal complement of Purkinje neurons. Of 14,563 probe sets expressed in wild-type cerebellum, 797 showed a significant (p
A measurement of the energy dependence of the inclusive yield of high-Pt events triggered by a large solid angle calorimeter

Abstract Large aperture calorimeter measurements of high transverse momentum events from 100, 200 and 340 GeV pp collisions are reported. Yields are higher by one to two orders of magnitude than the yield expected from uncorrelated statistical fluctuations in multiparticle events. The exponential slopes of the yields versus xt exhibited a systematic change with s (x t = 2P t / s ) . The events are shown to be more diffuse than pure jets as produced in e+e− collisions. However, these events are consistent with a QCD-inspired 4-jet model.
Electron Beam Fabrication Of Computer-Generated Holograms

We report here the development of an integrated capability for writing computer-generated holograms (CGHs) using either of two commercially available electron-beam lithography systems. These binary, chrome-on-glass holograms have been used extensively for aspheric optical testing and also have applications to the interferometric recording of holograms. Algorithms are described for encoding CGHs for drawing by e-beam systems. Limitations of e-beam CGH fabrication are discussed. A self-contact lithography and ion milling process is described for con-verting chrome-on-glass holograms into 40% efficient, environmentally durable all-glass holograms.
DIGATEC (Digital Gas Turbine Engine Control)

The basic operating principles of an electronic digital computer gas turbine engine control system are presented. Closed loop turbine discharge temperature and speed controls have been implemented; their feasibility was demonstrated through hybrid digital/analog simulation and actual tests of a GE J85 turbojet engine through the start mode to maximum afterburner. Control mode description and results of the analysis and experimental runs are given in this paper.Copyright © 1968 by ASME
Long-Range Policies for the U.S. Economy

This is the first of an occasional series in Challenge about how to reorient the U.S. economy comprehensively. Herbert Gans has provided a fine start for the series. Call it Gans's New Deal for a New Century.
Small molecular weight monodisperse nuclear RNA.

Abstract The nuceloplasm and nucleolus of HeLa cells contain six distinct low molecular weight species of RNA. Their size, as estimated from electrophoretic mobility, ranges from 100 to 180 nucleotides. These RNA species are long-lived and do not appear to be precursor to any cytoplasmic product. At least four of them are extensively methylated. Their base compositions range from 47 to 54% guanosine + cytidine. Similar species of nuclear RNA are found in mouse fibroblast cultures and in the developing chick embryo brain.
A rapid method for preparing phage λ DNA from agar plate lysates

Abstract We have developed a simple and rapid method to prepare phage λ DNA from agar-plate lysates. This method does not require purification of phage particles. Fifteen milliliters of lysate obtained from agar plates yields about 5 μg DNA. The enzyme inhibitors in this preparation are removed by an Elutip-d column. The DNA can be cut by various restriction enzymes and ligated.
Low-volume resuscitation with a polymerized bovine hemoglobin-based oxygen-carrying solution (HBOC-201) provides adequate tissue oxygenation for survival in a porcine model of controlled hemorrhage.

Background We have shown in a previous work that HBOC-201 is able to reverse anaerobic metabolism at low volumes in a porcine model of controlled hemorrhage. On the basis of these results, we hypothesize that low-volume resuscitation with HBOC-201 in a porcine model of controlled hemorrhage provides adequate tissue oxygenation to limit end-organ damage and allow for survival of the animal. Methods Twenty-four Yorkshire swine (55–65 kg) were rapidly hemorrhaged to a mean arterial pressure (MAP) of 30 mm Hg, maintained hypotensive for 45 minutes, and then divided into four groups. The first group, Shed Blood (BL), was resuscitated with shed blood to baseline MAP. A second group, Shed Blood (60), underwent resuscitation for four hours at an MAP of 60 mm Hg with shed blood. The third group, LR + Blood, was resuscitated with lactated Ringer’s (maximum, 40 mL/kg) followed by shed blood to baseline MAP. The final group, HBOC (60), underwent resuscitation for 4 hours at an MAP of 60 mm Hg with HBOC-201. Hemodynamic variables, urine output, blood gas analyses, lactate levels, and jejunal oximetry were followed throughout the experiment. Animals were allowed to survive and underwent necropsy on postinjury day 3. Histologic comparisons were made. Data were analyzed using analysis of variance/Duncan’s multiple range test. Results All animals survived the hemorrhage/resuscitation. One animal in the LR + Blood group died on postinjury day 1. Heart rate, MAP, and arterial pH were similar between groups. Cardiac output was significantly lower throughout resuscitation in the HBOC (60) group. Jejunal oximetry was similar throughout the experiment in all groups, revealing a decline in Po2 during hemorrhage and return to baseline or near baseline during resuscitation. There was no evidence of renal dysfunction. Histologically, one animal in the LR + Blood group and four of six animals in the HBOC (60) group demonstrated mild hepatocellular damage. All other tissues examined were found to have no significant abnormalities. Elevations in serum aspartate aminotransferase levels were noted when comparing the HBOC (60) group to the Shed Blood (BL) and Shed Blood (60) groups on day 2. Significant decreases in hemoglobin levels were noted in the HBOC (60) group compared with all other groups beginning on day 2. Conclusion Low-volume resuscitation with HBOC-201 provides adequate tissue oxygenation for survival in a porcine model of controlled hemorrhagic shock with no long-term organ dysfunction identified. Although some animals did show mild hepatocellular damage with elevations of aspartate aminotransferase at day 2, these findings did not appear to have clinical relevance, and the enzyme elevations were trending toward normal by the third postoperative day. Decreases in hemoglobin levels at the later time points were expected, given the half-life of the product.
Economics of resynchronization strategies including chemical tests to identify nonpregnant cows

Our objectives were to assess (1) the economic value of decreasing the interval between timed artificial insemination (TAI) services when using a pregnancy test that allows earlier identification of nonpregnant cows; and (2) the effect of pregnancy loss and inaccuracy of a chemical test (CT) on the economic value of a pregnancy test for dairy farms. Simulation experiments were performed using a spreadsheet-based decision support tool. In experiment 1, we assessed the effect of changing the interbreeding interval (IBI) for cows receiving TAI on the value of reproductive programs by simulating a 1,000-cow dairy herd using a combination of detection of estrus (30 to 80% of cows detected in estrus) and TAI. The IBI was incremented by 7d from 28 to 56 d to reflect intervals either observed (35 to 56 d) or potentially observed (28 d) in dairy operations. In experiment 2, we evaluated the effect of accuracy of the CT and additional pregnancy loss due to earlier testing on the value of reproductive programs. The first scenario compared the use of a CT 31 ± 3 d after a previous AI with rectal palpation (RP) 39 ± 3 d after AI. The second scenario used a CT 24 ± 3 d after AI or transrectal ultrasound (TU) 32 d after AI. Parameters evaluated included sensitivity (Se), specificity (Sp), questionable diagnosis (Qd), cost of the CT, and expected pregnancy loss. Sensitivity analysis was performed for all possible combinations of parameter values to determine their relative importance on the value of the CT. In experiment 1, programs with a shorter IBI had greater economic net returns at all levels of detection of estrus, and use of chemical tests available on the market today might be beneficial compared with RP. In experiment 2, the economic value of programs using a CT could be either greater or less than that of RP and TU, depending on the value for each of the parameters related to the CT evaluated. The value of the program using the CT was affected (in order) by (1) Se, (2) Sp, (3) pregnancy loss, (4) proportion of Qd, (5) percentage of cows AI in estrus, and (6) cost of CT. A change of 1% in the Se of the CT was 1.8 times more important than a similar change in Sp or pregnancy loss, and 13.7, 55.0, and 305.8 times more important than similar changes in Qd, cows inseminated in estrus, and cost of CT. We conclude that the major effect of using a CT is the potential of decreasing the IBI. Moreover, inaccuracy of the CT and additional pregnancy loss due to earlier testing resulted in smaller economic differences than when using RP or TU 8d later.