549 research outputs found
Interprocedural Reachability for Flat Integer Programs
We study programs with integer data, procedure calls and arbitrary call
graphs. We show that, whenever the guards and updates are given by octagonal
relations, the reachability problem along control flow paths within some
language w1* ... wd* over program statements is decidable in Nexptime. To
achieve this upper bound, we combine a program transformation into the same
class of programs but without procedures, with an Np-completeness result for
the reachability problem of procedure-less programs. Besides the program, the
expression w1* ... wd* is also mapped onto an expression of a similar form but
this time over the transformed program statements. Several arguments involving
context-free grammars and their generative process enable us to give tight
bounds on the size of the resulting expression. The currently existing gap
between Np-hard and Nexptime can be closed to Np-complete when a certain
parameter of the analysis is assumed to be constant.Comment: 38 pages, 1 figur
Expressiveness of Temporal Query Languages: On the Modelling of Intervals, Interval Relationships and States
Storing and retrieving time-related information are important, or even critical, tasks on many areas of Computer Science (CS) and in particular for Artificial Intelligence (AI). The expressive power of temporal databases/query languages has been studied from different perspectives, but the kind of temporal information they are able to store and retrieve is not always conveniently addressed. Here we assess a number of temporal query languages with respect to the modelling of time intervals, interval relationships and states, which can be thought of as the building blocks to represent and reason about a large and important class of historic information. To survey the facilities and issues which are particular to certain temporal query languages not only gives an idea about how useful they can be in particular contexts, but also gives an interesting insight in how these issues are, in many cases, ultimately inherent to the database paradigm. While in the area of AI declarative languages are usually the preferred choice, other areas of CS heavily rely on the extended relational paradigm. This paper, then, will be concerned with the representation of historic information in two well known temporal query languages: it Templog in the context of temporal deductive databases, and it TSQL2 in the context of temporal relational databases. We hope the results highlighted here will increase cross-fertilisation between different communities. This article can be related to recent publications drawing the attention towards the different approaches followed by the Databases and AI communities when using time-related concepts
Effects of vitamin D3 derivative--calcitriol on pharmacological reactivity of aortic rings in a rodent PCOS model.
Abstract
BACKGROUND:
The aim of this study was to examine the effects of the hyperandrogenic state in dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS), the vascular responses to different vasoactive agents, and the modulatory role of vitamin D3.
METHODS:
APCOS model was induced by DHT application in 20 female Wistar rats. Ten of the DHT treated rats simultaneously received calcitriol treatment. After 10 weeks, myographs were used to test the reactivity of isolated thoracic aortic rings to norepinephrine and acetylcholine. Thereafter, the vascular rings were incubated with the NO-synthase blocker (nitro-L-arginine methyl ester) or the cyclooxygenase inhibitor (indomethacin) for 20 min, and the effects of norepinephrine and acetylcholine were re-evaluated.
RESULTS:
Norepinephrine-induced vasoconstriction was enhanced after DHT treatment, but this effect was attenuated by calcitriol administration. Vasorelaxation of DHT-treated thoracic aortic rings was impaired, but this could be partly reversed by calcitriol application. Impaired NO-dependent vasorelaxation in DHT-treated animals was mostly reversed by concomitant calcitriol administration, but this effect was diminished by prostanoid-dependent vasoconstriction.
CONCLUSIONS:
These studies show that the enhanced sensitivity to vasoconstrictors and impaired NO-dependent vasorelaxation in hyperandrogenic PCOS rats could be partially reversed by calcitriol treatment
Clinical phenotype and genetic associations in autosomal dominant familial Alzheimer's disease: a case series
Background - The causes of phenotypic heterogeneity in familial Alzheimerâs disease with autosomal dominant inheritance are not well understood. We aimed to characterise clinical phenotypes and genetic associations with APP and PSEN1 mutations in symptomatic autosomal dominant familial Alzheimerâs disease (ADAD). Methods -
We retrospectively analysed genotypic and phenotypic data (age at symptom onset, initial cognitive or behavioural symptoms, and presence of myoclonus, seizures, pyramidal signs, extrapyramidal signs, and cerebellar signs) from all individuals with ADAD due to APP or PSEN1 mutations seen at the Dementia Research Centre in London, UK. We examined the frequency of presenting symptoms and additional neurological features, investigated associations with age at symptom onset, APOE genotype, and mutation position, and explored phenotypic differences between APP and PSEN1 mutation carriers. The proportion of individuals presenting with various symptoms was analysed with descriptive statistics, stratified by mutation type. Findings - Between July 1, 1987, and Oct 31, 2015, age at onset was recorded for 213 patients (168 with PSEN1 mutations and 45 with APP mutations), with detailed history and neurological examination findings available for 121 (85 with PSEN1 mutations and 36 with APP mutations). We identified 38 different PSEN1 mutations (four novel) and six APP mutations (one novel). Age at onset differed by mutation, with a younger onset for individuals with PSEN1 mutations than for those with APP mutations (mean age 43·6 years [SD 7·2] vs 50·4 years [SD 5·2], respectively, p<0·0001); within the PSEN1 group, 72% of age at onset variance was explained by the specific mutation. A cluster of five mutations with particularly early onset (mean age at onset <40 years) involving PSEN1âs first hydrophilic loop suggests critical functional importance of this region. 71 (84%) individuals with PSEN1 mutations and 35 (97%) with APP mutations presented with amnestic symptoms, making atypical cognitive presentations significantly more common in PSEN1 mutation carriers (n=14; p=0·037). Myoclonus and seizures were the most common additional neurological features; individuals with myoclonus (40 [47%] with PSEN1 mutations and 12 [33%] with APP mutations) were significantly more likely to develop seizures (p=0·001 for PSEN1; p=0·036 for APP), which affected around a quarter of the patients in each group (20 [24%] and nine [25%], respectively). A number of patients with PSEN1 mutations had pyramidal (21 [25%]), extrapyramidal (12 [14%]), or cerebellar (three [4%]) signs. Interpretation - ADAD phenotypes are heterogeneous, with both age at onset and clinical features being influenced by mutation position as well as causative gene. This highlights the importance of considering genetic testing in young patients with dementia and additional neurological features in order to appropriately diagnose and treat their symptoms, and of examining different mutation types separately in future research. Funding - Medical Research Council and National Institute for Health Research
Prospective longitudinal evaluation of treatment-related toxicity and health-related quality of life during the first year of treatment for pediatric acute lymphoblastic leukemia
Background: Pediatric acute lymphoblastic leukemia (ALL) therapy is accompanied by treatment-related toxicities (TRTs) and impaired quality of life. In Australia and New Zealand, children with ALL are treated with either Childrenâs Oncology Group (COG) or international Berlin-Frankfurt-Munster (iBFM) Study Group-based therapy. We conducted a prospective registry study to document symptomatic TRTs (venous thrombosis, neurotoxicity, pancreatitis and bone toxicity), compare TRT outcomes to retrospective TRT data, and measure the impact of TRTs on childrenâs general and cancer-related health-related quality of life (HRQoL) and parentsâ emotional well-being. Methods: Parents of children with newly diagnosed ALL were invited to participate in the ASSET (Acute Lymphoblastic Leukaemia Subtypes and Side Effects from Treatment) study and a prospective, longitudinal HRQoL study. TRTs were reported prospectively and families completed questionnaires for general (Healthy Utility Index Mark 3) and cancer specific (Pediatric Quality of Life Inventory (PedsQL)-Cancer Module) health related quality of life as well the Emotion Thermometer to assess emotional well-being. Results: Beginning in 2016, 260 pediatric patients with ALL were enrolled on the TRT registry with a median age at diagnosis of 59 months (range 1â213 months), 144 males (55.4%), majority with Pre-B cell immunophenotype, n = 226 (86.9%), 173 patients (66.5%) treated according to COG platform with relatively equal distribution across risk classification sub-groups. From 2018, 79 families participated in the HRQoL study through the first year of treatment. There were 74 TRT recorded, reflecting a 28.5% risk of developing a TRT. Individual TRT incidence was consistent with previous studies, being 7.7% for symptomatic VTE, 11.9% neurotoxicity, 5.4% bone toxicity and 5.0% pancreatitis. Childrenâs HRQoL was significantly lower than population norms throughout the first year of treatment. An improvement in general HRQoL, measured by the HUI3, contrasted with the lack of improvement in cancer-related HRQoL measured by the PedsQL Cancer Module over the first 12 months. There were no persisting differences in the HRQoL impact of COG compared to iBFM therapy. Conclusions: It is feasible to prospectively monitor TRT incidence and longitudinal HRQoL impacts during ALL therapy. Early phases of ALL therapy, regardless of treatment platform, result in prolonged reductions in cancer-related HRQoL
Enhanced superconductivity in Hf-base metallic glasses
Systematic study of electrical resistivity of Hf_{100-x}Fe_x (x=20,25),
Hf_{100-x}Cu_x (x=30,40,50), and Ti_{65}Cu_{35} metallic glasses has been done
in the temperature range 0.3 K - 290 K, and in magnetic fields B <= 5 T. All
Hf-base alloys are superconducting with T_c >= 0.44 K, which is well above T_c
of pure crystalline Hf (0.13 K). From the initial slopes of the upper critical
fields, (dH_{c2}/dT)_{T_c}, and resistivities we determined the dressed
electronic densities of states, N_{\gamma}(E_F), for all alloys. Both T_c and
N_{\gamma}(E_F) decrease with increasing x (Fe and Cu content). The results are
compared with those for corresponding Zr-base metallic glasses and
ion-implanted Hf films.Comment: 9 pages, 4 figures, 1 tabl
Genetic determinants of survival in progressive supranuclear palsy: a genome-wide association study.
BACKGROUND: The genetic basis of variation in the progression of primary tauopathies has not been determined. We aimed to identify genetic determinants of survival in progressive supranuclear palsy (PSP). METHODS: In stage one of this two stage genome-wide association study (GWAS), we included individuals with PSP, diagnosed according to pathological and clinical criteria, from two separate cohorts: the 2011 PSP GWAS cohort, from brain banks based at the Mayo Clinic (Jacksonville, FL, USA) and in Munich (Germany), and the University College London PSP cohort, from brain banks and the PROSPECT study, a UK-wide longitudinal study of patients with atypical parkinsonian syndromes. Individuals were included if they had clinical data available on sex, age at motor symptom onset, disease duration (from motor symptom onset to death or to the date of censoring, Dec 1, 2019, if individuals were alive), and PSP phenotype (with reference to the 2017 Movement Disorder Society criteria). Genotype data were used to do a survival GWAS using a Cox proportional hazards model. In stage two, data from additional individuals from the Mayo Clinic brain bank, which were obtained after the 2011 PSP GWAS, were used for a pooled analysis. We assessed the expression quantitative trait loci (eQTL) profile of variants that passed genome-wide significance in our GWAS using the Functional Mapping and Annotation of GWAS platform, and did colocalisation analyses using the eQTLGen and PsychENCODE datasets. FINDINGS: Data were collected and analysed between Aug 1, 2016, and Feb 1, 2020. Data were available for 1001 individuals of white European ancestry with PSP in stage one. We found a genome-wide significant association with survival at chromosome 12 (lead single nucleotide polymorphism rs2242367, p=7·5âĂâ10-10, hazard ratio 1·42 [95% CI 1·22-1·67]). rs2242367 was associated with survival in the individuals added in stage two (n=238; p=0·049, 1·22 [1·00-1·48]) and in the pooled analysis of both stages (n=1239; p=1·3âĂâ10-10, 1·37 [1·25-1·51]). An eQTL database screen revealed that rs2242367 is associated with increased expression of LRRK2 and two long intergenic non-coding RNAs (lncRNAs), LINC02555 and AC079630.4, in whole blood. Although we did not detect a colocalisation signal for LRRK2, analysis of the PSP survival signal and eQTLs for LINC02555 in the eQTLGen blood dataset revealed a posterior probability of hypothesis 4 of 0·77, suggesting colocalisation due to a single shared causal variant. INTERPRETATION: Genetic variation at the LRRK2 locus was associated with survival in PSP. The mechanism of this association might be through a lncRNA-regulated effect on LRRK2 expression because LINC02555 has previously been shown to regulate LRRK2 expression. LRRK2 has been associated with sporadic and familial forms of Parkinson's disease, and our finding suggests a genetic overlap with PSP. Further functional studies will be important to assess the potential of LRRK2 modulation as a disease-modifying therapy for PSP and related tauopathies. FUNDING: PSP Association, CBD Solutions, Medical Research Council (UK)
Optical properties of hydrogenated amorphous silicon
A detailed study of the optical properties of sputtered hydrogenated amorphous silicon films with varying hydrogen concentration is presented here. The energy dependence of the absorption coefficient is looked into, in detail, from a point of view of understanding the well known Tauc rule and the alternate relations being proposed in recent years. Spectroscopic and bandâstructural models like Wemple-Didomenico and Penn are then utilized to analyze the optical parameters near the bandâgap region of the wavelength spectra. Extensive comparisons of our results are made with those of sputtered aâSi:H films of other workers, glow discharge prepared aâSi:H, chemically vapor deposited and evaporated aâSi, and also crystalline silicon. The similarities in the variation of the optical properties of aâSi:H with increasing hydrogen concentration (or decreasing measurement temperature) to that of crystalline silicon with decreasing measurement temperature lead us to interesting conclusions. Thus, it seems that decreasing disorder (topological or thermal) in aâSi:H is equivalent to decreasing thermal disorder in câSi, at least as far as the disorderâoptical property relationships are concerned
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