bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring the Electronic Energy Spectrum On and Off the Fermi Surface
Authors: Ketterson J. B.
Published: December 2016

This chapter discusses various methods that have been used to measure the energy spectrum of electrons in both metals and insulators. For metals a property of paramount importance is the detailed shape of the Fermi surface and the accompanying Fermi velocity, since together they affect transport and other phenomena. Methods to measure these quantities include various magneto-acoustic effects (e.g., the geometric resonance phenomenon), the Gantmakher and Sondheimer size effects, the Azbel–Kaner cyclotron resonance, the anomalous skin effect, the high-field magneto-resistance (as it relates to open versus closed orbits), and various quantum oscillations, the most important of which is the de Hass–van Alphen effect. For determining the energy spectrum at energies below the Fermi surface, the most powerful technique is angle resolved photo-emission spectroscopy (ARPES) which, with the emergence of synchrotron sources, has become increasingly important. Also of growing importance is inverse photo-emission spectroscopy (IPS), a special case of which is termed bremsstrahlung isochromat spectroscopy (BIS). Here the roles of the incoming photon and the final state electron are reversed: electrons of known energy (and angle) impinge on the surface and (in the BIS variant) the energy spectrum of the emitted photons is measured. This technique probes the spectrum for energies above the Fermi energy.
Homogeneous Semiconductors
Authors: Ketterson J. B.
Published: December 2016

A semiconductor can be regarded as an insulator with a narrow band gap, εg. Semiconductors may be divided into two classes: those for which the points in k-space corresponding to the highest occupied valence band state, εv, and the lowest unoccupied conduction band state, εc, lie directly above each other (a direct band gap material); and those for which these two points are separated in k-space by some amount k0 (an indirect band gap material). At absolute zero, all the states associated with the valence bands are filled while those of the conduction bands are empty. The empty state is referred to as a hole. In the presence of an applied electric field, transitions will occur from the lower lying (occupied) electron state into the empty hole state, i.e., the hole will move lower in energy. However, since the hole represents the absence of an electron, this downward motion of the hole represents an increase in the energy of the system. In steady state, where the energy gained from an external potential drop is lost to the rest of the system through scattering, the hole will drift at a constant velocity. A completely filled band carries no current, and therefore the holes contribute a current of the opposite sign — they behave like positively charged electrons. This chapter discusses the following: parabolic bands, carrier densities and densities of states, band properties in some specific materials, holes in Si and Ge, impurity states, calculating the occupancy of donors and acceptors, carrier concentrations in the presence of donors and acceptors, impurity band conduction, and qualitative behavior on doping.
Inhomogeneous Semiconductors
Authors: Ketterson J. B.
Published: December 2016

This chapter begins by analyzing p–n junctions in equilibrium and in the presence of an electric field. A device called a diode, which possesses asymmetric characteristics for current flow in opposite directions, is made by forming a junction between a p-type material (containing only acceptor levels) and an n-type material (containing only donors). After contact, the materials come into chemical equilibrium by the exchange of electrons until their chemical potentials equilibrate. A more detailed theory of current transport in a p–n junction both in equilibrium and under an applied voltage is developed followed by discussions of the operation of a number of semiconductor devices. These include the diode rectifier, the p–n–p junction transistor, the tunnel diode, the junction laser, the Zener diode, the field effect transistor, and the MOSFET ((metal-oxide–semiconductor field effect transistor).
Electric and Magnetic Susceptibilities
Authors: Ketterson J. B.
Published: December 2016

This chapter begins by discussing the effects of an electric field. An external electric field, E, will exert a force on all the charged constituents of a material. This force results in a displacement of various charge centres that, in equilibrium and in an insulator, is balanced by fields induced by the displacements themselves; at finite frequencies one must also account for the inertia (mass) associated with the accelerated nuclei and electrons making up the system, ultimately in a manner consistent with quantum mechanics. Such charge displacements in the body produce dipole moments. To account for the effect of these dipoles one introduces a polarization, defined as the dipole moment per unit volume. The electric field also produces a force on all the electrons. The strong nuclear electric field tightly constrains the motion of the core electrons; their orbitals are nonetheless distorted by the external field resulting in a core contribution to the electronic polarization. The remainder of the chapter deals with static ionic polarizibility; the electronic polarizibility of atoms and molecules; and the magnetic susceptibility of atoms and molecules.
Optical Responses
Authors: Ketterson J. B.
Published: December 2016

Important information about the excitation spectra of semiconductors and insulators can be obtained by studying the frequency dependence of the absorption of light passing through the material. This chapter first introduces the matrix element for optical absorption spectra. At low temperatures, transitions take place only between the occupied valence band states and the unoccupied conduction band states. An expression is developed for the transition probability per unit time between two such states, wherein a matrix element — involving the perturbation Hamiltonian in Chapter 24 — connects the initial (valence band) state and the final (conduction band) state. The remainder of the chapter discusses the singular points in the optical absorption; the frequency-dependent susceptibility; some analytic properties of the susceptibility; the Kramers–Kronig relations; and some examples of optical spectra. Sample problems are also provided at the end of the chapter.
Polaritons, Excitons, and Plasmons
Authors: Ketterson J. B.
Published: December 2016

This chapter begins by deriving the Lyddane–Sachs–Teller relation. It then turns to excitons, which refer to states produced by a kind of excitation wherein an electron and hole are created, but they do not escape their mutual Coulomb attraction and end up in a bound electron–hole state. The binding energy and characteristic size of excitons varies widely among different materials. We may construct simple models for the limiting cases where the size of the excitons is much larger than, or of the order of, the spacing between the atoms. These limiting cases are referred to as Wannier and Frankel excitons, respectively, each of which is discussed in turn. The remainder of the chapter covers the exciton–polariton, plasmons, and surface polaritons. Sample problems are also given at the end of the chapter.
Behavior Under Intense Illumination: NLO, the e–h Liquid and Excitonic BEC
Authors: Ketterson J. B.
Published: December 2016

Chapter 29 examined the linear response of insulators and semiconductors to light, particularly with respect to optical absorption. With the availability of high intensity pulsed lasers it is now possible to study responses in the nonlinear regime where phenomena such as harmonic generation and frequency mixing occur as well as collective behaviors of the high densities of excitations being reduced. The latter is of interest in connection with the electron–hole liquid and Bose–Einstein condensation (BEC) of excitons, both of which are discussed in this chapter. Topics covered include the effects on quadratic (second order) and cubic (third order) susceptibilities on harmonic fields; Bose condensation in an ideal gas; the weakly interacting Bose gas for non-zero temperatures; and the Gross–Pitaevskii equation.
A Phenomenological Theory of Superconductivity: The Ginzburg–Landau Theory and the Josephson Effects
Authors: Ketterson J. B.
Published: December 2016

This chapter begins with an analysis of Ginzburg–Landau theory. The discussion in Chapter 32 has brought out the idea that superconductivity is some kind of macroscopic quantum state. Ginzburg and Landau built this idea into the Landau second-order phase transition theory by assuming the existence of a macroscopic ‘wave function’, which they took as the order parameter associated with superconductivity. The chapter then discusses boundaries and boundary conditions, the upper critical field and the phase diagram of a type II superconductor, the Josephson effects, magnetic field effects, and the behaviour of a single planar Josephson junction in a magnetic field. A sample problem is also provided at the end of the chapter.
Econometrics of Panel Data
Authors: Biørn Erik
Published: December 2016

Panel data is a data type increasingly used in research in economics, social sciences, and medicine. Its primary characteristic is that the data variation goes jointly over space (e.g. individuals, firms, countries) and time (e.g. years, months). Panel data allow examination of problems which cannot be handled by cross-section data or time-series data. Panel data analysis is a core field in modern econometrics and multivariate statistics, and studies based on such data occupy a growing part of the field in many other disciplines. The book is intended as a text for master’s/advanced undergraduate courses. It may also be useful for PhD students writing theses in empirical/applied economics and readers doing empirical work on their own. The book attempts to take the reader gradually from simple models and methods in scalar (simple vector) notation to more complex models in matrix notation. Compared to related texts, a distinctive feature is that relatively more attention is given to unbalanced panel data, the measurement error problem, random coefficient approaches, the interface between panel data and aggregation, and the interface between unbalanced panels and truncated and censored data sets. The 12 chapters are intended to be largely self-contained, although there is a natural progression. Most chapters contain commented examples based on genuine data, mainly taken from panel data applications to economics. Although the book, inter alia, through its use of examples, aims primarily at students of economics/econometrics, it may be useful also for readers in social sciences outside economics and in psychology and medicine, provided they have a sufficient background in statistics, notably basic regression analysis and elementary linear algebra.
Introduction
Authors: Biørn Erik
Published: December 2016

In this chapter, introductory surveys of types of panel data and their potential are given. Transformations to handle unobserved heterogeneity are exemplified. The introduction also includes brief comments on panel data in relation to aggregation and in relation to experimental and non-experimental data. An overview of the content of the book is given.
Regression analysis with unidimensional variables
Authors: Biørn Erik
Published: December 2016

This chapter introduces the reader to the basic properties of second-order moments and moment matrices involving unidimensional variables. One-way and two-way regression models containing unobserved fixed or random effects jointly with unidimensional regressors are considered. For the fixed effects versions, notable collinearity and identification problems arise, which may restrict the attraction of such models, are considered.
Dynamic models
Authors: Biørn Erik , Biørn Erik , Biørn Erik
Published: December 2016

The chapter considers first-order autoregressive models with individual-specific intercepts. Both the within estimator and OLS estimation of an equation in first-differences have notable deficiencies when the time-series are short. More relevant are estimators utilizing instrumental variables (IV) in levels for the equation in differences, or estimators using the opposite configuration. Procedures using orthogonal forward deviations are also considered. Versions of GMM are discussed, and extensions to handle disturbance memory are explained. For models with random effects, Maximum Likelihood (ML) and stepwise procedures are considered for equations containing both two-dimensional and individual-specific explanatory variables.
Rex Leptasta (Hist. II, 20)
Authors: Syme Ronald
Published: December 2016

This passage provides a discussion of a fragment of Sallust’s Histories that sheds light on an aspect of the Roman presence in Spain and North Africa, and of the history of the Sertorian War. The discussion deals with the wider strategy of Sertorius in the war against Rome and with the role that some sectors of the provincial elites played in that context. The figure of Vibius Paciaecus receives close consideration, as well as the place of the historian Fenestella in the tradition on Spain the late Republican period. A passage of Plutarch’s Life of Crassus suggests that the influence of this author was quite considerable, and that he had good first-hand knowledge of that region.
Sallust and Bestia
Authors: Syme Ronald
Published: December 2016

This paper provides a full discussion of the evidence of Sallust for L. Calpurnius Bestia’s involvement with the conspiracy of Catiline, and of other related prosopographical problems. The career of this important figure in late Republican politics, who had a strong connection with Cicero, receives a full overview, as well as the biographies of his descendants and their links with other sectors of the Roman nobility, notably the Sempronii Atratini. It is argued that Sallust’s interest in Bestia was linked with his involvement in the events of 43 bc; an analogy is drawn between him and the enigmatic character of the noblewoman Sempronia.
Sallust on Crassus
Authors: Syme Ronald
Published: December 2016

This paper is a study of the evidence of Sallust on Crassus and his political career and allegiances, as well as his relationship with Catilina. Crassus’s presence in Catiline’s War is surveyed in detail, as well as the possibility that Sallust may have reported an aspect of a conversation with Crassus in the monograph. Wider questions are addressed in this connection: the nature of the political ties between Crassus and Sallust, the overall judgement of Sallust on the role of Sulla and his associates, and the lack of the value of the evidence of the Invective against Cicero for late Republican politics. Some speculation is offered on the assessment of Crassus in Sallust’s Histories.
Sallust’s List of Conspirators
Authors: Syme Ronald
Published: December 2016

This note provides a prosopographical discussion of the list of adherents of Catiline’s conspiracy provided by Sallust. These characters belong to the senatorial and equestrian orders, and are named as follows. Senators: P. Lentulus Sura, P. Autronius, L. Cassius Longinus, C. Cethegus, P. and Ser. Sulla Ser. filii, L. Vargunteius, Q. Annius, M. Porcius Laeca, L. Bestia, Q. Curius. Knights: M. Fulvius Nobilior, L. Statilius, P. Gabinius Capito, and C. Cornelius. Their identities, social backgrounds, and political trajectories are explored in detail. Some omissions in Sallust’s list, such as P. Sulla, are also discussed, as well as the sources from which Sallust drew his information.
Cicero’s Change of Plan (August 7, 44 bc)
Authors: Syme Ronald
Published: December 2016

This discussion of the events of August 44 bc that led Cicero to stop his journey from Italy to Greece and return to Rome to regain a central role in Roman politics. Close consideration is given to the evidence of Cicero’s correspondence, as well as the later references to the crisis of Summer 44 in the Philippics. The dealings between Cicero and the Liberators play a central part in this connection, as well as the impact of the compromise between Antony and the assassins of Caesar. The motives that led Cicero to persevere with his plan to return to Rome from southern Italy even after he received news of that agreement receive some discussion.
Caesar and Augustus in Virgil
Authors: Syme Ronald
Published: December 2016

This paper provides a detailed discussion of the place of Julius Caesar in Virgil’s work and of the role that the memory of the former Dictator played in the Augustan period. Its main contention is that Virgil did share the unease with the legacy of Caesar that appears to characterise Octavian’s political discourse and much of the literary production of the Augustan period. The close reading of Virgil’s references to Caesar may therefore serve as a basis for wider conclusions on the formation and consolidation of consensus in the Triumviral and Augustan periods, and more generally on the reflection on late Republican history in that age.
Rome and Umbria
Authors: Syme Ronald
Published: December 2016

A study of the relationship between Rome and Umbria from the early Republic until the early Augustan period. Special emphasis is placed on the dynamics of military conquest, the impact of road-building, the legal arrangements devised with a number of communities in the region, the colony of Spoletium, and the position of the Umbrian elites in the late Republican civil wars. Chapters: I. Rome and Umbria; II. The Pacification of Umbria; III. Camerinum; IV. Spoletium and the Via Flaminia; V. Roman Annexations in Umbria; VI. Umbria in the Civil Wars; VII. Political Partisans from Spoletium; VIII. The Pietas of Calvisius Sabinus.
Fiction
Authors: Priest Graham
Published: December 2016

Chapter 6 provides a noneist account of fictional objects, and replies to some natural objections to the account.
Mathematical Objects and Worlds
Authors: Priest Graham
Published: December 2016

Chapter 7 provides a noneist account of mathematical and other abstract objects, and of worlds (possible and impossible). It then discusses a number of objections, such as that this is just a form of platonism in disguise.
Poor Non-Existent Objects
Authors: Priest Graham
Published: December 2016

Chapter 12 considers the objection that the non-existent objects delivered by the account of the book have too few properties. Several such reasons are considered and rejected. One objection does, however, require a fine-tuning of the account of descriptions offered in chapter 4.
Family and Inheritance
Authors: Barker Hannah
Published: December 2016

This chapter focuses on the beneficiaries of wills and the motivations of testators, arguing that will-making was primarily driven by a desire to control one’s property in accordance with a set of social norms that were powerfully influenced by religious belief and a sense of duty towards one’s immediate family, and particularly those who were considered to be dependants. This meant making sure that wives and children were provided for, that there was equity between children, and that wealth remained in the hands of those to whom it was bequeathed, with a particular concern to protect anything left to female relatives. There is also evidence of strong emotional bonds between family members and of the particular potency of blood and marital ties, and of a clear awareness among tradesmen and women of the broader contexts of their decision-making, and of the laws relating to inheritance.
Seawater Is More than Salted Water
Authors: Roy-Barman Matthieu , Jeandel Catherine
Published: December 2016

The chemical composition of seawater results from a combination of chemical and biological reactions and transport processes. The concentration of conservative elements is modified only by water mixing, whereas the concentration of minor or trace non-conservative elements is also sensitive to biological or chemical reactions. The distributions of nutrients such as nitrate, phosphate and silicate, as well as the oxygen concentration, are controlled by both ocean circulation and biological activity. Nutrients are consumed in surface water during photosynthesis and released in deep waters by remineralization of the sinking dead organic matter. Nutrients and oxygen are consumed and released in constant proportions called Redfield ratios. Most gases (including oxygen) are saturated with respect to the atmosphere in the surface water. The distinctive behavior of carbon dioxide comes from the carbonate system equilibria. The behavior of selected trace metals illustrates the respective roles of the redox reactions, complexation reactions and biological uptake.
Advection–Diffusion Models
Authors: Roy-Barman Matthieu , Jeandel Catherine
Published: December 2016

Advection–diffusion models provide a continuous description of tracers in the ocean. The advection–diffusion equation is obtained by combining the conservation equation for an infinitely small box with the equations describing advective and diffusive fluxes. The advection flux is proportional to the current speed and to the tracer concentration. Molecular diffusion is due to the random motion of molecules and the resulting net flux is given by the first Fick law. It is significant at the microscopic scale only like at the sea/air interface. Eddy diffusion is due to the more or less random motions of a turbulent fluid. By analogy with molecular diffusion, net flux is also calculated with the first Fick law. Integration of the advection-diffusion equation yields the spatial and temporal evolution of the tracer in the ocean. This is applied to radium transport in coastal waters and to the deliberate release of SF6 in the thermocline.
Development and Limitations of Biological Activity in Surface Waters
Authors: Roy-Barman Matthieu , Jeandel Catherine
Published: December 2016

Ocean life is organized in complex ecosystems fed by the photosynthesis of organic matter in the photic zone. The biological activity is seasonal because it is closely linked with nutrient repletion of the surface waters by winter convection. The subsequent nutrient consumption by phytoplankton depletes the surface waters and limits the biological activity. By recycling the organic matter produced by phytoplankton, heterotrophs prevent the loss of nutrients exported in the deep ocean by dead sinking organic matter. The ocean primary productivity can be measured in situ or estimated at the global scale by satellite observation of the ocean color. It is mainly driven by the winter mixed layer and the Ekman pumping that bring nutrient-rich deep waters to the ocean surface. Nitrate, phosphate, iron and silica exert the strongest limitation on biological productivity. Coastal regions are the most sensitive to the impacts of nthropogenic inputs that selectively favor algae development.
The Little World of Marine Particles
Authors: Roy-Barman Matthieu , Jeandel Catherine
Published: December 2016

Although they often represent a few tens of micrograms per liter, marine particles play a key role in the regulation of the ocean’s chemistry. They are diverse in nature (living or non-living, organic, mineral or mixed) and origin (indigenous, continental detritus, etc.). The operational classification of marine particles relies on sampling techniques: small suspended particles collected by filtration or large rapidly sinking particles collected with sediment traps. The particle size and density distributions control the particle flux through ballasting, aggregation/disaggregation and remineralization. Particle dynamics are elucidated with particle-reactive isotopes both at small scale (scavenging rates, settling speed) and large scale with the ocean margins appearing as both a sink and source region for chemical elements (boundary scavenging and boundary exchange). Ultimately, settling particles are incorporated in sediments. There, remineralization and diagenesis still modify their chemical composition on longer timescales and provide dissolved elements by diffusion through pore water.
Infectious disease risk and international tourism demand
Authors: Rosselló Jaume , Santana-Gallego Maria , Awan Waqas
Published: December 2016

Context For some countries, favourable climatic conditions for tourism are often associated with favourable conditions for infectious diseases, with the ensuing development constraints on the tourist sectors of impoverished countries where tourism’s economic contribution has a high potential. This paper evaluates the economic implications of eradication of Malaria, Dengue, Yellow Fever and Ebola on the affected destination countries focusing on the tourist expenditures.

Methods A gravity model for international tourism flows is used to provide an estimation of the impact of each travel-related disease on international tourist arrivals. Next the potential eradication of these diseases in the affected countries is simulated and the impact on tourism expenditures is estimated.

Findings The results show that, in the case of Malaria, Dengue, Yellow Fever and Ebola, the eradication of these diseases in the affected countries would result in an increase of around 10 million of tourist worldwide and a rise in the tourism expenditure of 12 billion dollars.

Conclusion By analysing the economic benefits of the eradication of Dengue, Ebola, Malaria, and Yellow Fever for the tourist sector—a strategic economic sector for many of the countries where these TRD are present—this paper explores a new aspect of the quantification of health policies which should be taken into consideration in future international health assessment programmes. It is important to note that the analysis is only made of the direct impact of the diseases’ eradication and consequently the potential multiplicative effects of a growth in the GDP, in terms of tourism attractiveness, are not evaluated. Consequently, the economic results can be considered to be skeleton ones.
Is It Time to Include CT “Reverse Halo Sign” and qPCR Targeting Mucorales in Serum to EORTC-MSG Criteria for the Diagnosis of Pulmonary Mucormycosis in Leukemia Patients?
Authors: Caillot Denis , Valot Stéphane , Lafon Ingrid , Basmaciyan Louise , Chretien Marie Lorraine , Sautour Marc , Millon Laurence , Legouge Caroline , Payssot Alexandre , Dalle Frédéric
Published: December 2016

In 23 leukemia patients with proven (n = 17) or possible (n = 6) pulmonary mucormycosis (PM), the presence of reversed halo sign on computed tomography was strongly associated with the positivity of quantitative polymerase chain reaction assays targeting Mucorales in the serum, confirming the value of these two tools for the diagnosis of PM in this setting.
Do Medical Students’ Narrative Representations of “The Good Doctor” Change Over Time? Comparing Humanism Essays From a National Contest in 1999 and 2013
Authors: Rutberg Pooja C. , King Brandy , Gaufberg Elizabeth , Brett-MacLean Pamela , Dinardo Perry , Frankel Richard M.
Published: December 2016

Purpose

To explore medical students’ conceptions of “the good doctor” at two points in time separated by 14 years.

Method

The authors conducted qualitative analysis of narrative-based essays. Following a constant comparative method, an emergent relational coding scheme was developed which the authors used to characterize 110 essays submitted to the Arnold P. Gold Foundation Humanism in Medicine Essay Contest in 1999 (n = 50) and 2013 (n = 60) in response to the prompt, “Who is the good doctor?”

Results

The authors identified five relational themes as guiding the day-to-day work and lives of physicians: doctor–patient, doctor–self, doctor–learner, doctor–colleague, and doctor–system/society/profession. The authors noted a highly similar distribution of primary and secondary relational themes for essays from 1999 and 2013. The majority of the essays emphasized the centrality of the doctor–patient relationship. Student essays focused little on teamwork, systems innovation, or technology use—all important developments in contemporary medicine.

Conclusions

Medical students’ narrative reflections are increasingly used as rich sources of information about the lived experience of medical education. The findings reported here suggest that medical students understand the “good doctor” as a relational being, with an enduring emphasis on the doctor–patient relationship. Medical education would benefit from including an emphasis on the relational aspects of medicine. Future research should focus on relational learning as a pedagogical approach that may support the formation of caring, effective physicians embedded in a complex array of relationships within clinical, community, and larger societal contexts.
Supporting the Call to Action: A Review of Nutrition Educational Interventions in the Health Professions Literature and MedEdPORTAL
Authors: Dang Timothy M. , Maggio Lauren A.
Published: December 2016

Purpose

Despite calls to improve nutrition education, training for medical students is inadequate. This systematic review provides an overview of published educational interventions for undergraduate-level health professionals and makes recommendations for improving nutrition training.

Method

The authors conducted a systematic review of articles (through July 16, 2015) and examined resources in MedEdPORTAL (through September 28, 2015) focused on materials published since January 2004 that describe nutrition educational interventions for undergraduate-level health professionals. The authors extracted data on pedagogical characteristics, content areas covered, study design, and study outcomes.

Results

Of 1,616 article citations, 32 met inclusion criteria. Most were designed at a single institution (n = 29) for medical students (n = 24). Of 51 MedEdPORTAL resources, 15 met inclusion criteria. Most were designed at a single institution (n = 12) for medical students (n = 15). Interventions spread across several countries, learner levels, and settings. Content areas covered included basic science nutrition, population health, counseling, and training framed by specific patient populations and organ systems. No clear trends were observed for intended learning outcomes, type of instructor, method of instruction, or duration.

Conclusions

The heterogeneity of interventions and the content areas covered highlight the lack of adopted curricular standards for teaching clinical nutrition. Recommendations that educators should consider include interprofessional education approaches, online learning, placing an emphasis on learners’ personal health behaviors, and standardized and real patient interactions. Educators should continue to publish curricular materials and prioritize the evaluation and sharing of resources.
Are Scores From NBME Subject Examinations Valid Measures of Knowledge Acquired During Clinical Clerkships?
Authors: Ryan Michael S. , Bishop Steven , Browning Joel , Anand Rahul J. , Waterhouse Elizabeth , Rigby Fidelma , Al-Mateen Cheryl S. , Lee Clifton , Bradner Melissa , Colbert-Getz Jorie M.
Published: December 2016

Purpose

The National Board of Medical Examiners’ Clinical Science Subject Examinations are a component used by most U.S. medical schools to determine clerkship grades. The purpose of this study was to examine the validity of this practice.

Method

This was a retrospective cohort study of medical students at the Virginia Commonwealth University School of Medicine who completed clerkships in 2012 through 2014. Linear regression was used to determine how well United States Medical Licensing Examination Step 1 scores predicted Subject Examination scores in seven clerkships. The authors then substituted each student’s Subject Examination standard scores with his or her Step 1 standard score. Clerkship grades based on the Step 1 substitution were compared with actual grades with the Wilcoxon rank test.

Results

A total of 2,777 Subject Examination scores from 432 students were included in the analysis. Step 1 scores significantly predicted between 23% and 44% of the variance in Subject Examination scores, P < .001 for all clerkship regression equations. Mean differences between expected and actual Subject Examination scores were small (≤ 0.2 points). There was a match between 73% of Step 1 substituted final clerkship grades and actual final clerkship grades.

Conclusions

The results of this study suggest that performance on Step 1 can be used to identify and counsel students at risk for poor performance on the Subject Examinations. In addition, these findings call into the question the validity of using scores from Subject Examinations as a high-stakes assessment of learning in individual clerkships.
Nonopioid Management of Neonatal Abstinence Syndrome
Authors: Boucher Anne-Marie
Published: December 2016

Background:

Current standard therapy for moderate to severe neonatal abstinence syndrome (NAS) includes opioid administration and often results in separation of mother and infant. Impaired maternal–infant bonding and extended neonatal opiate exposure may be associated with adverse developmental outcomes. Increased use of nonopioid adjunctive NAS therapies may decrease postnatal opioid exposure and length of stay (LOS), thereby promoting positive developmental outcomes for NAS-affected infants.

Purpose:

To review the efficacy of rooming-in care and acupuncture as nonpharmacologic adjunctive agents to reduce the magnitude of postnatal opioid exposure and LOS.

Methods:

PubMed, Ovid Medline, Embase, and CINAHL databases were searched for primary studies on rooming-in care and acupuncture as adjunctive treatments for NAS; 8 are included in this review.

Findings:

Rooming-in care may decrease postnatal opioid exposure and LOS in NAS-affected infants. Acupuncture is safe in NAS patients; however, its definitive effect on narcotic use and length of hospitalization are inconclusive.

Implications for Practice:

Rooming-in care should be offered to NAS patients. Strong evidence does not exist to recommend acupuncture as a routine NAS treatment.

Implications for Research:

Additional randomized clinical trials are necessary to assess the efficacy of acupuncture and to confirm the effect of rooming-in care on NAS outcomes, and delineate optimal elements of a rooming-in care model.
Trends in net survival from cervical cancer in six European Latin countries: results from the SUDCAN population-based study
Authors: Haelens Annemie , Roche Laurent , Bastos Joana , Woronoff Anne-Sophie , Zorzi Manuel , Francart Julie
Published: December 2016

Cancer survival is a key measure of the effectiveness of a healthcare system. As differences in healthcare systems are present among European Latin countries, it is of interest to look specifically at their similarities and differences in terms of cancer survival. Incident cases were extracted from the EUROCARE-V database for France, Italy, Spain, Switzerland, Portugal, and Belgium. One and 5-year net survivals (NS) were calculated for the period 2000–2004 using the Pohar-Perme estimator. Trends in NS over the 1992–2004 period and changes in the pattern of cancer excess mortality rate until 5 years after diagnosis were examined using a multivariate excess mortality rate model. There were moderate differences in age-standardized NS between countries (5-year NS range: 83–88%), but significant differences in the age groups 15–54 and 55–74 years (at 5 years up to +16 and +18% between any two countries). During the study period, excess mortality and NS improved in Italy, Spain, and Portugal. In Italy and Portugal, this improvement was slightly similar at ages 40, 55, and 70 whereas, in Spain, there was a sharp increase in NS at age 55. Because of this improvement, excess mortality and NS were similar in all six countries in 2004. Excess mortality peaked around 1 year after diagnosis in the youngest ages, but decreased gradually in the elderly. Detailed analyses showed differences in excess mortality and NS from cervical cancer between European Latin countries. However, these differences decreased over the study period because of the considerable improvement in Spain, Italy, and Portugal.
Trends in net survival from corpus uteri cancer in six European Latin countries: results from the SUDCAN population-based study
Authors: Antunes Luís , Roche Laurent , José Bento Maria
Published: December 2016

Corpus uteri cancer is the most common gynaecological cancer in women in Europe, but presents a relatively good prognosis. There were two main objectives in this study: estimate differences between countries in age-standardized net survival (NS) at 1 and 5 years in 2000–2004 and evaluate time trends in NS and excess mortality rates in 1992–2004. Data on corpus uteri malignant tumours (International Classification of Diseases for Oncology, third ed.: C54) were extracted from the EUROCARE database for six European Latin countries: Belgium, France, Italy, Portugal, Spain and Switzerland. NS was estimated for each country using the nonparametric estimator proposed by Pohar-Perme. Trends in NS and excess mortality rates up to 5 years after diagnosis were assessed using a multivariable parametric flexible modelling. The study analysed 25 508 cases for the first objective and 43 550 for the second. Age-standardized 1-year NS ranged from 88% (Portugal and Spain) to 93% (Switzerland), whereas 5-year survival ranged between 72% (Portugal) and 79% (Belgium and Switzerland). From 1992 to 2004, the NS increased in all countries with available information on this period (France, Italy, Spain and Switzerland). Also, in Belgium and Portugal, there was an increase in NS between 2000 and 2004. Improvements in survival were more evident for older ages (75 years). There were some differences in NS between the countries studied (maximum of 5% at 1 year and 7% at 5 years). The NS improved in all countries during the period studied and the differences between countries narrowed.
Trends in net survival from head and neck cancer in six European Latin countries: results from the SUDCAN population-based study
Authors: Guizard Anne-Valérie , Uhry Zoé , de Raucourt Dominique , Mazzoleni Guido , Sánchez Maria-José , Ligier Karine
Published: December 2016

The aim of the SUDCAN collaborative study was to compare the trends in 1- and 5-year net survival and the trends in the dynamics of the excess mortality rates in head and neck cancers between six European Latin countries (Belgium, France, Italy, Portugal, Spain and Switzerland). The data were extracted from the EUROCARE-5 database. First, the net survival was studied over the 2000–2004 period using the Pohar-Perme estimator. For trend analyses, the study period was specific to each country. The results are reported from 1992 to 2004 in France, Italy, Spain and Switzerland and from 2000 to 2004 in Belgium and Portugal. The analyses were carried out using a flexible excess rate modelling. There were significant differences between countries in 5-year age-standardized net survivals over the 2000–2004 period, ranging from 33 to 34% in France and Portugal from 42 to 44% in Switzerland and Italy, respectively. The age-standardized net survival improved considerably from 1992 to 2004 in Italy, Spain and Switzerland, but not in France because of lack of improvement in the elderly. The increase in net survival was linked to a decrease in the excess mortality rate up to 3–4 years after diagnosis. The net survival from head and neck cancers improved over the study period, but significant differences were still observed in 2004. Differences in sex ratio and anatomical distribution contributed only partially towards these disparities. Differences in stage at diagnosis, time to treatment and/or proportion of human papillomavirus-related cases are also probably involved in the survival disparities observed. Overall, the prognosis of these tumours remains poor.
Trends in net survival lung cancer in six European Latin countries: results from the SUDCAN population-based study
Authors: Bordoni Andrea , Uhry Zoé , Antunes Luis
Published: December 2016

Survival is a key measure of the effectiveness of a healthcare system. European Latin countries have some similarities in their health systems; it is thus interesting to examine their differences in survival from cancer, here, lung cancer. The aim of the SUDCAN collaborative study was to compare the trends in the 1- and 5-year net survival from lung cancer and the trends in the excess mortality rates between six European Latin countries (Belgium, France, Italy, Portugal, Spain and Switzerland). The data were extracted from the EUROCARE-5 database. First, the net survival was studied over the 2000–2004 period using Pohar-Perme estimator. For trend analyses, the study period was specific to each country. The results are reported from 1992 to 2004 in France, Italy, Spain and Switzerland and from 2000 to 2004 in Belgium and Portugal. The analyses were carried out using a flexible excess rate modelling. Overall, the 1-year net survival from lung cancer ranged between 36 (Spain) and 43% (Belgium and Switzerland) and the 5-year net survival ranged between 11 (Spain) and 15% (Belgium and Switzerland). Between 1992 and 2004, the age-standardized survival increased considerably at 1 year, but increased less at 5 years after diagnosis. This increase was observed at ages 60 and 70, but was less obvious at age 80. There was little difference in net survival from lung cancer between European Latin countries, particularly in the more recent years. However, survival was slightly lower in Spain and Portugal than in France, Italy, Belgium and Switzerland. High-resolution studies with data on treatment, stage at diagnosis and comorbidities are needed to understand the reasons for these differences.
Trends in net survival from prostate cancer in six European Latin countries: results from the SUDCAN population-based study
Authors: Grosclaude Pascale , Roche Laurent , Fuentes-Raspall Rafael , Larrañaga Nerea
Published: December 2016

Cancer survival is a key measure of the effectiveness of a health-care system. European Latin countries have some differences in their health system; therefore, it is of interest to compare them in terms of survival from cancer. Prostate cancer data from six countries (Belgium, France, Italy, Portugal, Spain, and Switzerland) were extracted from the EUROCARE-5 database (end of follow-up: 1 January 2009). First, the net survival (NS) was studied over the 2000–2004 period using the Pohar-Perme estimator. For trend analyses, the study period was specific to each country. Trends in NS over the 1989–2004 period and changes in the pattern of cancer excess mortality rate until 5 years after the diagnosis were examined using a multivariate excess mortality rate model. A striking increase in survival from prostate cancer occurred in European Latin countries at all ages studied. In the last period of the study, there was little difference in age-standardized NSs from prostate cancer between the six countries. The trends of the survival followed those of the incidence (except in Spain in the elderly); the increases in incidence were the highest at ages 60–70 years and, in the elderly (around 80 years), the incidence did not increase in Switzerland. The increases in NS can mainly be explained by lead-time and overdiagnosis effects. The epidemiological interpretability of the changes in prostate cancer survival in Latin countries is strongly compromised by the biases inherent to the extensive prostate-specific antigen testing.
Trends in net survival from rectal cancer in six European Latin countries: results from the SUDCAN population-based study
Authors: Lepage Côme , Bossard Nadine , Dejardin Olivier , Carmona-Garcia Maria C. , Manfredi Sylvain , Faivre Jean
Published: December 2016

Rectal cancer is a common and serious disease. The aim of the SUDCAN collaborative study was to compare the net survival from rectal cancer between six European Latin countries (Belgium, France, Italy, Portugal, Spain, and Switzerland) and provide trends in net survival and dynamics of excess mortality rates up to 5 years after diagnosis. The data were extracted from the EUROCARE-5 database. First, net survival was studied over the period 2000–2004 using the Pohar-Perme estimator. For trend analyses, the study-period was specific to each country. The results are reported from 1992 to 2004 in France, Italy, Spain, and Switzerland and from 2000 to 2004 in Belgium and Portugal. These analyses were carried out using a flexible excess rate modeling strategy. There were some differences between countries in age-standardized net survivals (2000–2004). The 5-year survival ranged from 55% (Portugal) to 62% (Belgium). There was an increase in age-standardized survival rates between 1992 and 2004 as observed at 1 and 5 years. This increase was observed in the 60 and 70-year age groups, but was less marked in the 80-year age group. This was related to a decrease in the excess mortality rates between 1992 and 2004, until ∼24 months after diagnosis in France and Switzerland, whereas it was continuous over the entire study period in Italy and Spain. Considerable improvements in survival from rectal cancer have been achieved. Further improvements are expected through better adherence to the guidelines and the implementation of mass screening.
Low–Molecular-Weight Heparin for the Prevention of Placenta-mediated Pregnancy Complications
Authors: HADDAD BASSAM , LECARPENTIER EDOUARD , TOUBOUL CYRIL , SIBAI BAHA M.
Published: December 2016

During the past decade, prophylactic doses of low–molecular-weight heparin (LMWH) have been suggested to decrease the risk of placental-mediated complications. Herein, we review the prospective randomized trials that addressed the usefulness of LMWH in preventing placental-mediated complications in high-risk women. Inclusion criteria and results of these trials are heterogeneous. Unlike older trials (3 of 4 are single center), recent trials (all are multicenter) do not show beneficial effect of LMWH. There is certainly a need of complementary research before stating on the usefulness of LMWH in the prevention of placenta-mediated pregnancy complications in women at high risk.
Diagnosis and Management of HELLP Syndrome Complicated by Liver Hematoma
Authors: DITISHEIM AGNÈS , SIBAI BAHA M.
Published: December 2016

Subcapsular liver hematoma is a rare but potentially life-threatening complication of preeclampsia and hemolysis, elevated liver enzymes, and low platelets syndrome. It may present with nonspecific signs and symptoms, none of which are diagnostic, and can mimic pulmonary embolism of cholecystitis. There is no consensus on the management of subcapsular liver hematoma. Unruptured liver hematoma can be conservatively managed. When rupture occurs, surgical, endovascular approaches and, rarely, liver transplantation, may be required. Actual literature is scant and retrospective in nature. Data on follow-up, time to resolution and outcome of subsequent pregnancies are very limited. We here review the diagnosis and management of liver hematoma.