Bayesian optimization (BO) has been a successful approach to optimize expensive functions whose prior knowledge can be specified by means of a probabilistic model. Due to their expressiveness and tractable closed-form predictive distributions, Gaussian process (GP) surrogate models have been the default go-to choice when deriving BO frameworks. However, as nonparametric models, GPs offer very little in terms of interpretability and informative power when applied to model complex physical phenomena in scientific applications. In addition, the Gaussian assumption also limits the applicability of GPs to problems where the variables of interest may highly deviate from Gaussianity. In this article, we investigate an alternative modeling framework for BO which makes use of sequential Monte Carlo (SMC) to perform Bayesian inference with parametric models. We propose a BO algorithm to take advantage of SMC’s flexible posterior representations and provide methods to compensate for bias in the approximations and reduce particle degeneracy. Experimental results on simulated engineering applications in detecting water leaks and contaminant source localization are presented showing performance improvements over GP-based BO approaches.

Background. In this study we examined the prevalence rates of post-traumatic stress disorder (PTSD), types of trauma most often associated with PTSD, the co-morbidity of PTSD with other lifetime psychiatric disorders, which disorders preceded PTSD, and gender differences in PTSD and trauma exposure in a representative sample of Chileans.

Method. The DSM-III-R PTSD and antisocial personality disorder modules from the Diagnostic Interview Schedule (DIS) and modules for a range of DSM-III-R diagnoses from the Composite International Diagnostic Interview (CIDI) were administered to a representative sample of 2390 persons aged 15 to over 64 years in three cities in Chile.

Results. The lifetime prevalence of PTSD was 4·4% (2·5% for men and 6·2% for women). Among persons exposed to trauma, rape was most strongly associated with PTSD. Onset of PTSD significantly increased the risk of developing each of the 10 other tested disorders. Among those exposed to trauma, women were significantly more likely to develop PTSD, after controlling for assaultive violence.

Conclusions. This study highlights the importance of investigating the prevalence of PTSD, patterns of co-morbidity of PTSD, and gender differences in PTSD in non-English-speaking countries.

Background. In order to improve care for people with depressive disorders and to reduce the increasing burden of depression, the American Regional Office of the World Health Organization has launched a major region-wide initiative. A central part of this effort was directed to the primary care system where the diagnosis and treatment of depression are deficient in many countries. This study evaluated the materials developed by the World Psychiatric Association in a training program on depression among primary care physicians by measuring changes in their knowledge, attitudes, and practice (KAP).

Method. One hundred and seven physicians and 6174 patients from five Latin American countries participated in the trial. KAP were assessed 1 month before and 1 month following the training program. In addition, the presence of depressive symptoms was measured in patients who visited the clinic during a typical week at both times using the Zung Depression Scale and a DSM-IV/ICD-10 major depression checklist.

Results. The program slightly improved knowledge about depression and modified some attitudes, but had limited impact on actual practice. There was no evidence that the diagnosis of depression was made more frequently, nor was there an improvement in psychopharmacological management. The post-training agreement between physician diagnosis and that based on patient self-report remained low. The physicians, however, seemed more confident in treating depressed patients after training, and referred fewer patients to psychiatrists.

Conclusions. Traditional means of training primary care physicians in depression have little impact on clinical practice regardless of the quality of the teaching materials.

Praziquantel, the drug of choice against schistosomiasis, disrupts calcium (Ca2+) homeostasis in schistosomes via an unknown mechanism. Voltage-gated Ca2+ channels are heteromultimeric transmembrane protein complexes that contribute to impulse propagation and also regulate intracellular Ca2+ levels. β subunits modulate the properties of the pore-forming α1 subunit of high voltage-activated Ca2+ channels. Unlike other Ca2+ channel β subunits, which have current stimulatory effects, a β subunit subtype found in S. mansoni (SmβA) and S. japonicum (Sjβ) dramatically reduces current levels when co-expressed with Ca2+ channel α1 subunits in Xenopus oocytes. It also confers praziquantel sensitivity to the mammalian Cav2.3 α1 subunit. The Beta Interaction Domains (BIDs) of SmβA and Sjβ lack 2 conserved serines that each constitute a consensus site for protein kinase C (PKC) phosphorylation. Here, we use site-directed mutagenesis of schistosome β subunits to show that these unique functional properties are correlated with the absence of these consensus PKC sites in the BID. Furthermore, a second schistosome β subunit subtype contains both serines in the BID, enhances currents through α1 subunits, and does not confer praziquantel sensitivity. Thus, phosphorylation sites in the BID may play important roles in defining the modulatory properties and pharmacological sensitivities of schistosome Ca2+ channel β subunits.

Voltage-gated calcium (Ca2+) channels contribute to impulse propagation in excitable cells and also regulate intracellular levels of Ca2+. High voltage-activated (HVA) Ca2+ channels are heteromultimeric membrane proteins. The pore-forming, voltage-sensing subunit is the α1 subunit. We have cloned 3 HVA Ca2+ channel α1 subunit cDNAs from Schistosoma mansoni. One of these sequences most closely resembles the L-type class of HVA α1 subunits. The other two sequences are most closely related to non L-type α1 subunits. These schistosome α1 subunits have many of the features common to HVA Ca2+ channels, but also have distinct structural motifs. Analysis of the structural and functional properties of schistosome Ca2+ channel subunits may provide information about these critical components of excitable cells.

We examine the singularly perturbed variational problem in the plane. As ε → 0, this functional favours |∇ψ| = 1 and penalizes singularities where |∇∇ψ| concentrates. Our main result is a compactness theorem: if {Eε(ψε)}ε↓0 is uniformly bounded, then {∇ψε}ε↓0 is compact in L2. Thus, in the limit ε → 0, ψ solves the eikonal equation |∇ψ| = 1 almost everywhere. Our analysis uses ‘entropy relations’ and the ‘div-curl lemma,’ adopting Tartar's approach to the interaction of linear differential equations and nonlinear algebraic relations.

Bhattacharya and Kohn have used small-strain (geometrically linear) elasticity to analyze the recoverable strains of shape-memory polycrystals. The adequacy of small-strain theory is open to question, however, since some shape-memory materials recover as much as 10 percent strain. This paper provides the first progress toward an analogous geometrically nonlinear theory. We consider a model problem, involving polycrystals made from a two-variant elastic material in two space dimensions. The linear theory predicts that a polycrystal with sufficient symmetry can have no recoverable strain. The nonlinear theory corrects this to the statement that a polycrystal with sufficient symmetry can have recoverable strain no larger than the 3/2 power of the transformation strain. This result is in a certain sense optimal. Our analysis makes use of Fritz John's theory of deformations with uniformly small strain.

We develop a new approach to the modeling of thin film growth. Our model treats the adatom density on the surface of the film as an explict unknown. This approach (1) clarifies the role of the “uphill current” associated with the Schwoebel barrier; (2) facilitates simple, physically natural coupling to the mechanism of deposition; and (3) permits discussion of multispecies effects. Our implementation focuses on spiral mode growth of YBCO thin films, with MOCVD (Metallorganic chemical vapor deposition) as the deposition mechanism.

The backfitting algorithm is an iterative procedure for fitting additive models in which, at each step, one component is estimated keeping the other components fixed, the algorithm proceeding component by component and iterating until convergence. Convergence of the algorithm has been studied by Buja, Hastie, and Tibshirani (1989). We give a simple, but more general, geometric proof of the convergence of the backfitting algorithm when the additive components are estimated by penalized least squares. Our treatment covers spline smoothers and structural time series models, and we give a full discussion of the degenerate case. Our proof is based on Halperin's (1962) generalization of von Neumann's alternating projection theorem.

We consider the following question: given a set of matrices with no rank-one connections, does it support a nontrivial Young measure limit of gradients? Our main results are these: (a) a Young measure can be supported on four incompatible matrices; (b) in two space dimensions, a Young measure cannot be supported on finitely many incompatible elastic wells; (c) in three or more space dimensions, a Young measure can be supported on three incompatible elastic wells; and (d) if supports a nontrivial Young measure with mean value 0, then the linear span of must contain a matrix of rank one.