Evaluating machine learning techniques for archaeological lithic sourcing: a case study of flint in Britain

The original version of this Article contained errors in the legends of Figure 8 and 9. The legend of Figure 8: “Learning curve shows F1 score for train and test data against number of observations in training data.” now reads: “Box Plot of F1 Scores for each model, showing good equality of variances.

Intraoperative Cortical Localization of Music and Language Reveals Signatures of Structural Complexity in Posterior Temporal Cortex

Language and music involve the productive combination of basic units into structures. It remains unclear whether brain regions sensitive to linguistic and musical structure are co-localized. We report an intraoperative awake craniotomy in which a left-hemispheric language-dominant professional musician underwent cortical stimulation mapping (CSM) and electrocorticography of music and language perception and production during repetition tasks. Musical sequences were melodic or amelodic, and differed in algorithmic compressibility (Lempel-Ziv complexity). Auditory recordings of sentences differed in syntactic complexity (single vs. multiple phrasal embeddings). CSM of posterior superior temporal gyrus (pSTG) disrupted music perception and production, along with speech production. pSTG and posterior middle temporal gyrus (pMTG) activated for language and music (broadband gamma; 70-150 Hz). pMTG activity was modulated by musical complexity, while pSTG activity was modulated by syntactic complexity. This points to shared resources for music and language comprehension, but distinct neural signatures for the processing of domain-specific structural features

A Perturbative/Variational Approach to Quantum Lattice Hamiltonians

We propose a method to construct the ground state $\psi(\lambda)$ of local lattice hamiltonians with the generic form $H_0 + \lambda H_1$, where $\lambda$ is a coupling constant and $H_0$ is a hamiltonian with a non degenerate ground state $\psi_0$. The method is based on the choice of an exponential ansatz $\psi(\lambda) = {\rm exp}(U(\lambda)) \psi_0$, which is a sort of generalized lattice version of a Jastrow wave function. We combine perturbative and variational techniques to get succesive approximations of the operator $U(\lambda)$. Perturbation theory is used to set up a variational method which in turn produces non perturbative results. The computation with this kind of ansatzs leads to associate to the original quantum mechanical problem a statistical mechanical system defined in the same spatial dimension. In some cases these statistical mechanical systems turn out to be integrable, which allow us to obtain exact upper bounds to the energy. The general ideas of our method are illustrated in the example of the Ising model in a transverse field.Comment: 27 pages, three .ps figures appended, DFTUZ 94-2

Deriving and critiquing an empirically-based framework for pharmaceutical ethics.

Background: The pharmaceutical industry has been responsible for major medical advances, but the industry has also been heavily criticized. Such criticisms, and associated regulatory responses, are no doubt often warranted, but do not provide a framework for those who wish to reason systematically about the moral dimensions of drug development. We set out to develop such a framework using Beauchamp and Childress’s “four principles” as organizing categories. Methods: We conducted a qualitative interview study of people working in the “medical affairs” departments of pharmaceutical companies to determine: (1) whether our data could meaningfully be organized under the headings of “autonomy,” “beneficence,” “nonmaleficence,” and “justice”; (2) how principles might be expressed in this particular commercial setting; and (3) if these principles are expressed, whether and how competing principles are balanced. We then critiqued these findings using existing normative theory. Results: Our interviews demonstrated that three of Beauchamp and Childress’ four principles were salient to our participants: beneficence, non-maleficence, and justice. Within each of these principles, participants had two broad ethical orientations: an altruistic public focus (“other-ness”) and a commitment to their companies (“firm-ness”). Our participants also demonstrated efforts to balance these principles and highlighted the importance of phronesis (or practical wisdom) in balancing and enacting principles. Notably, however, our participants did not spontaneously emphasize the importance of autonomy. Conclusions: It is possible to use qualitative empirical research, together with normative analysis, to derive a framework for pharmaceutical ethics. We suggest that our framework would be useful for those who wish to reason ethically within, or in collaboration with, the pharmaceutical industry. Keywords: Empirical ethics, principle-based ethics, pharmaceutical industry, pharmaceutical ethics, qualitative researchNHMRC Career Development Fellowship APP106356

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Decision to take osteoporosis medication in patients who have had a fracture and are 'high' risk for future fracture: A qualitative study

Abstract Background Patients' values and preferences are fundamental tenets of evidence-based practice, yet current osteoporosis (OP) clinical guidelines pay little attention to these issues in therapeutic decision making. This may be in part due to the fact that few studies have examined the factors that influence the initial decision to take OP medication. The purpose of our study was to examine patients' experiences with the decision to take OP medication after they sustained a fracture. Methods A phenomenological qualitative study was conducted with outpatients identified in a university teaching hospital fracture clinic OP program. Individuals aged 65+ who had sustained a fragility fracture within 5 years, were 'high risk' for future fracture, and were prescribed OP medication were eligible. Analysis of interview data was guided by Giorgi's methodology. Results 21 patients (6 males, 15 females) aged 65-88 years participated. All participants had low bone mass; 9 had OP. Fourteen patients were taking a bisphosphonate while 7 patients were taking no OP medications. For 12 participants, the decision to take OP medication occurred at the time of prescription and involved minimal contemplation (10/12 were on medication). These patients made their decision because they liked/trusted their health care provider. However, 4/10 participants in this group indicated their OP medication-taking status might change. For the remaining 9 patients, the decision was more difficult (4/9 were on medication). These patients were unconvinced by their health care provider, engaged in risk-benefit analyses using other information sources, and were concerned about side effects; 7/9 patients indicated that their OP medication-taking status might change at a later date. Conclusions Almost half of our older patients who had sustained a fracture found the decision to take OP medication a difficult one. In general, the decision was not considered permanent. Health care providers should be aware of their potential role in patients' decisions and monitor patients' decisions over time

Calcium carbonate veins in ocean crust record a threefold increase of seawater Mg/Ca in the past 30 Million years

Chemical (Sr, Mg) and isotopic (δ18O, 87Sr/86Sr) compositions of calcium carbonate veins (CCV) in the oceanic basement were determined to reconstruct changes in Sr/Ca and Mg/Ca of seawater in the Cenozoic. We examined CCV from 10 basement drill sites in the Atlantic and Pacific, ranging in age between 165 and 2.3 Ma. Six of these sites are from cold ridge flanks in basement <46 Ma, which provide direct information about seawater composition. CCV of these young sites were dated, using the Sr isotopic evolution of seawater. For the other sites, temperature-corrections were applied to correct for seawater–basement exchange processes. The combined data show that a period of constant/low Sr/Ca (4.46–6.22 mmol/mol) and Mg/Ca (1.12–2.03 mol/mol) between 165 and 30 Ma was followed by a steady increase in Mg/Ca ratios by a factor of three to modern ocean composition. Mg/Ca–Sr/Ca relations suggest that variations in hydrothermal fluxes and riverine input are likely causes driving the seawater compositional changes. However, additional forcing may be involved in explaining the timing and magnitude of changes. A plausible scenario is intensified carbonate production due to increased alkalinity input to the oceans from silicate weathering, which in turn is a result of subduction-zone recycling of CO2 from pelagic carbonate formed after the Cretaceous slow-down in ocean crust production rate

Magnetic Resonance Elastography Shear Wave Velocity Correlates with Liver Fibrosis and Hepatic Venous Pressure Gradient in Adults with Advanced Liver Disease

Background. Portal hypertension, an elevation in the hepatic venous pressure gradient (HVPG), can be used to monitor disease progression and response to therapy in cirrhosis. Since obtaining HVPG measurements is invasive, reliable noninvasive methods of assessing portal hypertension are needed. Methods. Noninvasive markers of fibrosis, including magnetic resonance elastography (MRE) shear wave velocity, were correlated with histologic fibrosis and HVPG measurements in hepatitis C (HCV) and/or HIVinfected patients with advanced liver disease enrolled in a clinical trial of treatment with simtuzumab, an anti-LOXL2 antibody. Results. This exploratory analysis includes 23 subjects: 9 with HCV monoinfection, 9 with HIV and HCV, and 5 with HIV and nonalcoholic steatohepatitis. Median Ishak fibrosis score was 4 (range 1-6); 11 subjects (48%) had cirrhosis. Median HVPG was 6 mmHg (range 3-16). Liver stiffness measured by MRE correlated with HVPG ( = 0.64, = 0.01), histologic fibrosis score ( = 0.71, = 0.004), noninvasive fibrosis indices, including APRI ( = 0.81, &lt; 0.001), and soluble LOXL2 ( = 0.82, = 0.001). On stepwise multivariate regression analysis, MRE was the only variable independently associated with HVPG ( 2 = 0.377, = 0.02). Conclusions. MRE of the liver correlated independently with HVPG. MRE is a valid noninvasive measure of liver disease severity and may prove to be a useful tool for noninvasive portal hypertension assessment. Trial Registration Number. This trial is registered with NCT01707472

Speciation and fate of trace metals in estuarine sediments under reduced and oxidized conditions, Seaplane Lagoon, Alameda Naval Air Station (USA)

We have identified important chemical reactions that control the fate of metal-contaminated estuarine sediments if they are left undisturbed (in situ) or if they are dredged. We combined information on the molecular bonding of metals in solids from X-ray absorption spectroscopy (XAS) with thermodynamic and kinetic driving forces obtained from dissolved metal concentrations to deduce the dominant reactions under reduced and oxidized conditions. We evaluated the in situ geochemistry of metals (cadmium, chromium, iron, lead, manganese and zinc) as a function of sediment depth (to 100 cm) from a 60 year record of contamination at the Alameda Naval Air Station, California. Results from XAS and thermodynamic modeling of porewaters show that cadmium and most of the zinc form stable sulfide phases, and that lead and chromium are associated with stable carbonate, phosphate, phyllosilicate, or oxide minerals. Therefore, there is minimal risk associated with the release of these trace metals from the deeper sediments contaminated prior to the Clean Water Act (1975) as long as reducing conditions are maintained. Increased concentrations of dissolved metals with depth were indicative of the formation of metal HS(- )complexes. The sediments also contain zinc, chromium, and manganese associated with detrital iron-rich phyllosilicates and/or oxides. These phases are recalcitrant at near-neutral pH and do not undergo reductive dissolution within the 60 year depositional history of sediments at this site. The fate of these metals during dredging was evaluated by comparing in situ geochemistry with that of sediments oxidized by seawater in laboratory experiments. Cadmium and zinc pose the greatest hazard from dredging because their sulfides were highly reactive in seawater. However, their dissolved concentrations under oxic conditions were limited eventually by sorption to or co-precipitation with an iron (oxy)hydroxide. About 50% of the reacted CdS and 80% of the reacted ZnS were bonded to an oxide-substrate at the end of the 90-day oxidation experiment. Lead and chromium pose a minimal hazard from dredging because they are bonded to relatively insoluble carbonate, phosphate, phyllosilicate, or oxide minerals that are stable in seawater. These results point out the specific chemical behavior of individual metals in estuarine sediments, and the need for direct confirmation of metal speciation in order to constrain predictive models that realistically assess the fate of metals in urban harbors and coastal sediments