Learning Deep Belief Networks from Non-Stationary Streams

Deep learning has proven to be beneficial for complex tasks such as classifying images. However, this approach has been mostly applied to static datasets. The analysis of non-stationary (e.g., concept drift) streams of data involves specific issues connected with the temporal and changing nature of the data. In this paper, we propose a proof-of-concept method, called Adaptive Deep Belief Networks, of how deep learning can be generalized to learn online from changing streams of data. We do so by exploiting the generative properties of the model to incrementally re-train the Deep Belief Network whenever new data are collected. This approach eliminates the need to store past observations and, therefore, requires only constant memory consumption. Hence, our approach can be valuable for life-long learning from non-stationary data streams. © 2012 Springer-Verlag

Invasive candidiasis as a cause of sepsis in the critically ill patient.

Invasive fungal infections are an increasingly frequent etiology of sepsis in critically ill patients causing substantial morbidity and mortality. Candida species are by far the predominant agent of fungal sepsis accounting for 10% to 15% of health-care associated infections, about 5% of all cases of severe sepsis and septic shock and are the fourth most common bloodstream isolates in the United States. One-third of all episodes of candidemia occur in the intensive care setting. Early diagnosis of invasive candidiasis is critical in order to initiate antifungal agents promptly. Delay in the administration of appropriate therapy increases mortality. Unfortunately, risk factors, clinical and radiological manifestations are quite unspecific and conventional culture methods are suboptimal. Non-culture based methods (such as mannan, anti-mannan, β-d-glucan, and polymerase chain reaction) have emerged but remain investigational or require additional testing in the ICU setting. Few prophylactic or pre-emptive studies have been performed in critically ill patients. They tended to be underpowered and their clinical usefulness remains to be established under most circumstances. The antifungal armamentarium has expanded considerably with the advent of lipid formulations of amphotericin B, the newest triazoles and the echinocandins. Clinical trials have shown that the triazoles and echinocandins are efficacious and well tolerated antifungal therapies. Clinical practice guidelines for the management of invasive candidiasis have been published by the European Society for Clinical Microbiology and Infectious Diseases and the Infectious Diseases Society of North America

Bench-to-bedside review: Candida infections in the intensive care unit.

Invasive mycoses are life-threatening opportunistic infections and have emerged as a major cause of morbidity and mortality in critically ill patients. This review focuses on recent advances in our understanding of the epidemiology, diagnosis and management of invasive candidiasis, which is the predominant fungal infection in the intensive care unit setting. Candida spp. are the fourth most common cause of bloodstream infections in the USA, but they are a much less common cause of bloodstream infections in Europe. About one-third of episodes of candidaemia occur in the intensive care unit. Until recently, Candida albicans was by far the predominant species, causing up to two-thirds of all cases of invasive candidiasis. However, a shift toward non-albicans Candida spp., such as C. glabrata and C. krusei, with reduced susceptibility to commonly used antifungal agents, was recently observed. Unfortunately, risk factors and clinical manifestations of candidiasis are not specific, and conventional culture methods such as blood culture systems lack sensitivity. Recent studies have shown that detection of circulating beta-glucan, mannan and antimannan antibodies may contribute to diagnosis of invasive candidiasis. Early initiation of appropriate antifungal therapy is essential for reducing the morbidity and mortality of invasive fungal infections. For decades, amphotericin B deoxycholate has been the standard therapy, but it is often poorly tolerated and associated with infusion-related acute reactions and nephrotoxicity. Azoles such as fluconazole and itraconazole provided the first treatment alternatives to amphotericin B for candidiasis. In recent years, several new antifungal agents have become available, offering additional therapeutic options for the management of Candida infections. These include lipid formulations of amphotericin B, new azoles (voriconazole and posaconazole) and echinocandins (caspofungin, micafungin and anidulafungin)

Peripheral and central mechanisms involved in hormonal control of male and female reproduction

Reproduction involves the integration of hormonal signals acting across multiple systems togenerate a synchronized physiological output. A critical component of reproduction is the luteinizinghormone (LH) surge, which is mediated by estradiol (E2) and neuroprogesterone interacting tostimulate kisspeptin release in the rostral periventricular nucleus of the third ventricle in rats. Recentevidence has shown that both classical and membrane E2 and progesterone signaling is involved inthis pathway. A metabolite of gonadotropin-releasing hormone (GnRH), GnRH-(1-5), has been shownto stimulate GnRH expression, secretion, and has a role in the regulation of lordosis. Additionally,gonadotropin-inhibitory hormone (GnIH) projects to and influences the activity of GnRH neurons inbirds. Stress-induced changes in GnIH have been shown to alter breeding behaviors in birds,demonstrating another molecular control of reproduction. Peripherally, paracrine and autocrineactions within the gonad have been suggested as therapeutic targets for infertility in both males andfemales. Dysfunction of testicular prostaglandin synthesis is a possible cause of idiopathic maleinfertility. Indeed, local production of melatonin and corticotropin-releasing hormone (CRH) couldinfluence spermatogenesis via immune pathways in the gonad. In females, vascular endothelialgrowth factor A (VEGF-A) has been implicated in an angiogenic process that mediates developmentof the corpus luteum and thus fertility via the Notch signaling pathway. Age-induced decreases infertility involve ovarian kisspeptin and its regulation of ovarian sympathetic innervation. Finally,morphological changes in the arcuate nucleus of the hypothalamus influence female sexualreceptivity in rats. The processes mediating these morphological changes have been shown toinvolve rapid effects of E2 controlling synaptogenesis in this hypothalamic nucleus. Together, thisreview highlights new research in these areas, focusing on recent findings in the molecularmechanisms of central and peripheral hormonal control of reproduction.Fil: Rudolph, L. M.. University of California at Los Angeles; Estados UnidosFil: Bentley, G. E.. University of California Berkeley; Estados UnidosFil: Calandra, Ricardo Saul. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Paredes, A. H.. Universidad de Chile; ChileFil: Tesone, Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Wu, T. J.. Uniformed Services University; Estados UnidosFil: Micevych, P. E.. University of California at Los Angeles; Estados Unido

Chiral spin texture in the charge-density-wave phase of the correlated metallic Pb/Si(111) monolayer

We investigate the 1/3 monolayer $\alpha$-Pb/Si(111) surface by scanning tunneling spectroscopy (STS) and fully relativistic first-principles calculations. We study both the high-temperature $\sqrt{3}\times\sqrt{3}$ and low-temperature $3\times 3$ reconstructions and show that, in both phases, the spin-orbit interaction leads to an energy splitting as large as $25\%$ of the valence-band bandwidth. Relativistic effects, electronic correlations and Pb-substrate interaction cooperate to stabilize a correlated low-temperature paramagnetic phase with well-developed lower and upper Hubbard bands coexisting with $3\times3$ periodicity. By comparing the Fourier transform of STS conductance maps at the Fermi level with calculated quasiparticle interference from non-magnetic impurities, we demonstrate the occurrence of two large hexagonal Fermi sheets with in-plane spin polarizations and opposite helicities.Comment: 5 pages, 3 figure

Effects of magnetism and doping on the electron-phonon coupling in BaFe2_{2}As2_{2}

We calculate the effect of local magnetic moments on the electron-phonon coupling in BaFe$_{2}$As$_{2}+\delta$ using the density functional perturbation theory. We show that the magnetism enhances the total electron-phonon coupling by $\sim 50$, up to $\lambda \lesssim 0.35$, still not enough to explain the high critical temperature, but strong enough to have a non-negligible effect on superconductivity, for instance, by frustrating the coupling with spin fluctuations and inducing order parameter nodes. The enhancement comes mostly from a renormalization of the electron-phonon matrix elements. We also investigate, in the rigid band approximation, the effect of doping, and find that $\lambda$ versus doping does not mirror the behavior of the density of states; while the latter decreases upon electron doping, the former does not, and even increases slightly.Comment: 4 pages, 3 figure

Hyperprolactinemia induced by hCG leads to metabolic disturbances in female mice

The metabolic syndrome is a growing epidemic; it increases the risk for diabetes, cardiovascular disease, fatty liver, and several cancers. Several reports have indicated a link between hormonal imbalances and insulin resistance or obesity. Transgenic (TG) female mice overexpressing the human chorionic gonadotropin β-subunit (hCGβ+ mice) exhibit constitutively elevated levels of hCG, increased production of testosterone, progesterone and prolactin, and obesity. The objective of this study was to investigate the influence of hCG hypersecretion on possible alterations in the glucose and lipid metabolism of adult TG females. We evaluated fasting serum insulin, glucose, and triglyceride levels in adult hCGβ+ females and conducted intraperitoneal glucose and insulin tolerance tests at different ages. TG female mice showed hyperinsulinemia, hypertriglyceridemia, and dyslipidemia, as well as glucose intolerance and insulin resistance at 6 months of age. A 1-week treatment with the dopamine agonist cabergoline applied on 5-week-old hCGβ+ mice, which corrected hyperprolactinemia, hyperandrogenism, and hyperprogesteronemia, effectively prevented the metabolic alterations. These data indicate a key role of the hyperprolactinemia-induced gonadal dysfunction in the metabolic disturbances of hCGβ+ female mice. The findings prompt further studies on the involvement of gonadotropins and prolactin on metabolic disorders and might pave the way for the development of new therapeutic strategies.Fil: Ratner, Laura Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Stevens, Guillermina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bonaventura, Maria Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Lux, Victoria Adela R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Poutanen, Matti. University of Turku; FinlandiaFil: Calandra, Ricardo Saul. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Huhtaniemi, Ilpo T.. University of Turku; FinlandiaFil: Rulli, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

From antiferromagnetism to d-wave superconductivity in the 2D t-J model

We have found that the two dimensional t-J model, for the physical parameter range J/t = 0.4 reproduces the main experimental qualitative features of High-Tc copper oxide superconductors: d-wave superconducting correlations are strongly enhanced upon small doping and clear evidence of off diagonal long range order is found at the optimal doping \delta ~ 0.15. On the other hand antiferromagnetic long range order, clearly present at zero hole doping, is suppressed at small hole density with clear absence of antiferromagnetism at \delta >~ 0.1.Comment: 4 pages, 5 figure

Cefepime monotherapy for the empirical treatment of fever in granulocytopenic cancer patients

In a pilot study, we evaluated the efficacy and the safety of cefepime, a new cephalosporin with extended-spectrum activity against both Gram-positive and Gram-negative bacteria, as empirical monotherapy for 108 febrile episodes in 84 granulocytopenic cancer patients. Cefepime (2 g tds) was given for a minimum of 7 days or until resolution of infection. Of the 108 episodes, 91 were evaluable. Microbiologically documented infections occurred in 25 patients (27%) (18 Gram-positive, 7 Gram-negative), of whom 18 had bacteraemia. Infection was clinically documented in 47 patients (52%) and fever was unexplained in 19 (21%). Overall, 71% (65/91) of the infections resolved. Response rates were 86% (6/7) for Gram-negative infections, 44% (8/18) for Gram-positive infections (57%%for cefepime-susceptible Gram-positive bacteria), 77% (36/47) for clinically documented infections and 79% (15/19) for unexplained fevers. Of the 26 patients (29%) whose primary infections did not improve with cefepime monotherapy, 23 responded after the addition of other antibiotics. Sixteen patients (18%) developed secondary infections of which 13 were microbiologically documented; Gram-positive bacteria were isolated from seven patients, Gram-negative bacteria from two, fungi from three and a virus from one. Adverse effects were mild and did not require premature discontinuation of therapy except for one patient who developed an immediate allergic reaction after the first dose of cefepime from which he recovered fully. The survival rate after resolution of granulocytopenia was 96%; three patients died of primary bacterial infection and one from secondary disseminated candidiasis. In this pilot study, cefepime monotherapy appeared safe and effective as empirical therapy for fever in cancer patients with granulocytopenia. Whether cefepime is superior to other advanced-generation cephalosporins for the treatment of Gram-positive infections will require evaluation in a larger comparative stud

Impact of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry on the Clinical Management of Patients With Gram-negative Bacteremia: A Prospective Observational Study.

Background. Early identification of pathogens from blood cultures using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry may optimize the choice of empirical antibiotic therapy in the setting of bloodstream infections. We aimed to assess the impact of this new technology on the use of antibiotic treatment in patients with gram-negative bacteremia. Methods. We conducted a prospective observational study from January to December 2010 to evaluate the sequential and separate impacts of Gram stain reporting and MALDI-TOF bacterial identification performed on blood culture pellets in patients with gram-negative bacteremia. The primary outcome was the impact of MALDI-TOF on empirical antibiotic choice. Results. Among 202 episodes of gram-negative bacteremia, Gram stain reporting had an impact in 42 cases (20.8%). MALDI-TOF identification led to a modification of empirical therapy in 71 of all 202 cases (35.1%), and in 16 of 27 cases (59.3%) of monomicrobial bacteremia caused by AmpC-producing Enterobacteriaceae. The most frequently observed impact was an early appropriate broadening of the antibiotic spectrum in 31 of 71 cases (43.7%). In total, 143 of 165 episodes (86.7%) of monomicrobial bacteremia were correctly identified at genus level by MALDI-TOF. Conclusions. In a low prevalence area for extended spectrum betalactamases (ESBL) and multiresistant gram-negative bacteria, MALDI-TOF performed on blood culture pellets had an impact on the clinical management of 35.1% of all gram-negative bacteremia cases, demonstrating a greater impact than Gram stain reporting. Thus, MALDI-TOF could become a vital second step beside Gram stain in guiding the empirical treatment of patients with bloodstream infection