1,421 research outputs found

    k-Spectra of weakly-c-Balanced Words

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    A word uu is a scattered factor of ww if uu can be obtained from ww by deleting some of its letters. That is, there exist the (potentially empty) words u1,u2,...,unu_1,u_2,..., u_n, and v0,v1,..,vnv_0,v_1,..,v_n such that u=u1u2...unu = u_1u_2...u_n and w=v0u1v1u2v2...unvnw = v_0u_1v_1u_2v_2...u_nv_n. We consider the set of length-kk scattered factors of a given word w, called here kk-spectrum and denoted \ScatFact_k(w). We prove a series of properties of the sets \ScatFact_k(w) for binary strictly balanced and, respectively, cc-balanced words ww, i.e., words over a two-letter alphabet where the number of occurrences of each letter is the same, or, respectively, one letter has cc-more occurrences than the other. In particular, we consider the question which cardinalities n= |\ScatFact_k(w)| are obtainable, for a positive integer kk, when ww is either a strictly balanced binary word of length 2k2k, or a cc-balanced binary word of length 2kc2k-c. We also consider the problem of reconstructing words from their kk-spectra

    Do Horizontal Saccadic Eye Movements Increase Interhemispheric Coherence? Investigation of a Hypothesized Neural Mechanism Underlying EMDR

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    Series of horizontal saccadic eye movements (EMs) are known to improve episodic memory retrieval in healthy adults and to facilitate the processing of traumatic memories in eye movement desensitization and reprocessing (EMDR) therapy. Several authors have proposed that EMs achieve these effects by increasing the functional connectivity of the two brain hemispheres, but direct evidence for this proposal is lacking. The aim of this study was to investigate whether memory enhancement following bilateral EMs is associated with increased interhemispheric coherence in the electroencephalogram (EEG). Fourteen healthy young adults were asked to freely recall lists of studied neutral and emotional words after a series of bilateral EMs and a control procedure. Baseline EEG activity was recorded before and after the EM and control procedures. Phase and amplitude coherence between bilaterally homologous brain areas were calculated for six frequency bands and electrode pairs across the entire scalp. Behavioral analyses showed that participants recalled more emotional (but not neutral) words following the EM procedure than following the control procedure. However, the EEG analyses indicated no evidence that the EMs altered participants’ interhemispheric coherence or that improvements in recall were correlated with such changes in coherence. These findings cast doubt on the interhemispheric interaction hypothesis, and therefore may have important implications for future research on the neurobiological mechanism underlying EMDR

    Autosomal Dominant Polycystic Kidney Disease: 2009 Update for Internists

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    Because autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic abnormalities seen in today's medical practice, many internists will likely treat patients affected by this condition. Genetic abnormalities have been increasingly recognized, and the pathophysiology of the disease is beginning to be unraveled. Because of advances in imaging technology, surrogate markers for disease progression have allowed clinical studies of newer therapeutic agents to proceed. In the near future, therapies for this common genetic disease may be available to either prevent or stabilize the disease course for many affected individuals

    Trimethoprim-sulfamethoxazole in cyst fluid from autosomal dominant polycystic kidneys

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    Trimethoprim-sulfamethoxazole in cyst fluid from autosomal dominant polycystic kidneys. Cyst infection in patients with autosomal-dominant polycystic kidney disease (ADPKD) is often refractory to therapy, in part because of the limited entry of commonly used antibiotics into cyst fluid. To study the efficacy of trimethoprim-sulfamethoxazole in cyst infection, cyst fluid was obtained by percutaneous aspiration or at surgery from eight patients with ADPKD receiving trimethoprim-sulfamethoxazole. Cysts were categorized as nongradient or gradient by cyst-fluid sodium concentration. Trimethoprim-sulfamethoxazole concentrations within cysts were determined and cyst fluid inhibitory and bactericidal titers were assessed in vitro against Escherichia coli, Proteus mirabilis and Streptococcus fecalis. The mean cyst fluid trimethoprim and sulfamethoxazole concentrations were 15.2 µg/ml and 42.5 µg/ml, respectively. Preferential accumulation of trimethoprim was observed in gradient cysts, exceeding serum levels more than eightfold. Sulfamethoxazole penetrated cysts to a lesser extent, with. concentrations ranging from 10 to 70 percent of the serum level. Cyst fluid sampled prior to trimethoprim-sulfamethoxazole administration (control) demonstrated no antibacterial activity, while cyst fluid inhibitory and bactericidal titers following antibiotic administration were 1:32 or greater in most instances. These studies indicate that trimethoprim-sulfamethoxazole is likely to be efficacious in the treatment of cyst infection in polycystic kidneys

    When I relive a positive me: Vivid autobiographical memories facilitate autonoetic brain activation and enhance mood

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    Autobiographical memory is vital for our well-being and therefore used in therapeutic interventions. However, not much is known about the (neural) processes by which reliving memories can have beneficial effects. This study investigates what brain activation patterns and memory characteristics facilitate the effectiveness of reliving positive autobiographical memories for mood and sense of self. Particularly, the role of vividness and autonoetic consciousness is studied. Participants (N= 47) with a wide range of trait self-esteem relived neutral and positive memories while their bold responses, experienced vividness of the memory, mood, and state self-esteem were recorded. More vivid memories related to better mood and activation in amygdala, hippocampus and insula,indicative of increased awareness of oneself (i.e., prereflective aspect of autonoetic con-sciousness). Lower vividness was associated with increased activation in the occipital lobe, PCC, and precuneus, indicative of a more distant mode of reliving. While individuals with lower trait self-esteem increased in state self-esteem, they showed less deacti-vation of the lateral occipital cortex during positive memories. In sum, the vividness of the memory seemingly distinguished a more immersed and more distant manner of memory reliving. In particular, when reliving positive memories higher vividness facilitated increased prereflective autonoetic consciousness, which likely is instrumental in boosting mood
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