Cost-Sensitive Classification Methods for the Detection of Smuggled Nuclear Material in Cargo Containers

Classification problems arise in so many different parts of life – from sorting machine parts to diagnosing a disease. Humans make these classifications utilizing vast amounts of data, filtering observations for useful information, and then making a decision based on a subjective level of cost/risk of classifying objects incorrectly. This study investigates the translation of the human decision process into a mathematical problem in the context of a border security problem: How does one find special nuclear material being smuggled inside large cargo crates while balancing the cost of invasively searching suspect containers against the risk of al lowing radioactive material to escape detection? This may be phrased as a classification problem in which one classifies cargo containers into two categories – those containing a smuggled source and those containing only innocuous cargo. This task presents numerous challenges, e.g., the stochastic nature of radiation and the low signal-to-noise ratio caused by background radiation and cargo shielding. In the course of this work, we will break the analysis of this problem into three major sections – the development of an optimal decision rule, the choice of most useful measurements or features, and the sensitivity of developed algorithms to physical variations. This will include an examination of how accounting for the cost/risk of a decision affects the formulation of our classification problem. Ultimately, a support vector machine (SVM) framework with F -score feature selection will be developed to provide nearly optimal classification given a constraint on the reliability of detection provided by our algorithm. In particular, this can decrease the fraction of false positives by an order of magnitude over current methods. The proposed method also takes into account the relationship between measurements, whereas current methods deal with detectors independently of one another

Can uptake length in strams be determined by nutrient addition experiments? Results from an interbiome comparison study

Nutrient uptake length is an important parnmeter tor quantifying nutrient cycling in streams. Although nutrient tracer additions are the preierred method for measuring uptake length under ambient nutrient concentrations, short-term nutrient addition experiments have more irequently been used to estimate uptake length in streams. Theoretical analysis of the relationship between uptake length determined by nutrient addition experiments (Sw\u27) and uptake length determined by tracer additions (Sw)predicted that Sw\u27 should be consistently longer than 5, , and that the overestimate of uptake length by Sw( should be related to the level of nutrient addition above ambient concentrations and the degree of nutrient limitation. To test these predictions, we used data irom an interbiorne study of NH,- uptake length in which 15NH,- tracer and short-term NH,-a ddition experiments were performed in 10 streams using a uniform experimental approach. The experimental results largely contirmed the theoretical predictions: sw\u27 was consistently longer than Sw and Sw\u27:Sw ratios were directly related to the level of NH,- addition and to indicatvrs of N limitation. The experimentally derived Sw\u27:Sw, ratios were used with the theoretical results to infer the N limitation status of each stream. Together, the theoretical and experimental results showed the tracer experiments should be used whenever possible to determine nutrient uptake length in streams. Nutrient addition experiments may be useful for comparing uptake lengths between different streams or cliiferent times in the same stream. however, provided that nutrient additions are kept as low as possible and of similar miagnitude

Factors affecting ammonium uptake in streams - an inter-biome perspective

The Lotic Intersite Nitrogen experiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and from desert to rainforest. Measurements at each site included physical, hydraulic and chemical characteristics, biological parameters, whole-stream metabolism and ammonium uptake. Ammonium uptake was measured by injection of \u275~-ammonium and downstream measurements of 15N-ammonium concentration. 3. We found no general, statistically significant relationships that explained the variability in ammonium uptake among sites. However, this approach does not account for the multiple mechanisms of ammonium uptake in streams. When we estimated biological demand for inorganic nitrogen based on our measurements of in-stream metabolism, we found good correspondence between calculated nitrogen demand and measured assimilative nitrogen uptake. 4. Nitrogen uptake varied little among sites, reflecting metabolic compensation in streams in a variety of distinctly different biomes (autotrophic production is high where allochthonous inputs are relatively low and vice versa). 5. Both autotrophic and heterotrophic metabolism require nitrogen and these biotic processes dominate inorganic nitrogen retention in streams. Factors that affect the relative balance of autotrophic and heterotrophic metabolism indirectly control inorganic nitrogen uptake

Open science in archaeology

No abstract available

Sorl1 as an Alzheimer's disease predisposition gene?

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressively disabling impairments in memory, cognition, and non-cognitive behavioural symptoms. Sporadic AD is multifactorial and genetically complex. While several monogenic mutations cause early-onset AD and gene alleles have been suggested as AD susceptibility factors, the only extensively validated susceptibility gene for late-onset AD is the apolipoprotein E (APOE) epsilon4 allele. Alleles of the APOE gene do not account for all of the genetic load calculated to be responsible for AD predisposition. Recently, polymorphisms across the neuronal sortilin-related receptor (SORL1) gene were shown to be significantly associated with AD in several cohorts. Here we present the results of our large case-control whole-genome scan at over 500,000 polymorphisms which presents weak evidence for association and potentially narrows the association interval

Sex differences in the diagnosis of advanced cancer and subsequent outcome in people with chronic kidney disease: an analysis of a national population cohort

Background: In the general population, advanced cancer stage at presentation is associated with poorer health outcomes. People with chronic kidney disease (CKD) have increased incidence and mortality from most cancer types. We sought to determine whether people with CKD were more likely to present with advanced stage cancer, whether this was associated with survival, and whether these associations varied by sex. Methods: Data were from Secure Anonymised Information Linkage Databank (SAIL), a Welsh primary care database with linkage to cancer and death registries. We included patients with a de- novo cancer diagnosis (2011-2017), and at least two kidney function tests in the two years prior to diagnosis. Estimated glomerular filtration rate based on serum creatinine (eGFRcr) was calculated using the CKD-EPI 2009 equation (mL/min/1.73m2). Logistic regression models determined odds of presenting with advanced cancer (stage 3 or 4 at diagnosis) by different values of eGFRcr at baseline. Cox proportional hazards models tested associations between eGFRcr at baseline and all-cause mortality risk (reference eGFR 75 to <90). Findings: There were 66,128 patients: 30,857 (46.7%) were female, mean age was 69.1 (standard deviation [SD] 13.8) years in females and 70.6 (SD 11.1) years in males; median eGFRcr at baseline was 78 (interquartile range [IQR] 63 – 90) mL/min/1.73m2 in both females and males. Over a median follow-up time of 3.1 (IQR 0.5 – 5.7) years in females and 2.9 (IQR 0.5-5.5) years in males, there were 17,303 deaths in females and 20,855 in males. An eGFRcr <30 was associated with higher odds of presenting with advanced cancer in males (OR 1.33 95% CI 1.09-1.62), but not in females (OR 1.17 95% CI 0.92-1.50); positive associations were primarily driven by prostate and breast cancers. With lower eGFRcr, hazards of cancer death increased in both sexes, but lower eGFRcr was associated with greater hazards of cancer death in females (eGFRcr <30: HR 1.71, 95% CI 1.56-1.88, p<0.001; male versus female comparison HR 0.88, 95% CI 0.78-0.90; p=0.037). Interpretation: CKD was not associated with substantially higher odds of presenting with advanced cancer across most cancer sites (except prostate and breast), but was associated with reduced survival. Despite an initial survival advantage compared to males, females with CKD had disproportionately higher hazards of death. Though potential explanations for reduced survival after a cancer diagnosis are manifold, scrutiny of access to, efficacy, and safety of cancer treatments in people with CKD – particularly females with CKD – are warranted

Sporadic naturally occurring melanoma in dogs as a preclinical model for human melanoma

Melanoma represents a significant malignancy in humans and dogs. Different from genetically engineered models, sporadic canine melanocytic neoplasms share several characteristics with human disease that could make dogs a more relevant preclinical model. Canine melanomas rarely arise in sun-exposed sites. Most occur in the oral cavity, with a subset having intra-epithelial malignant melanocytes mimicking the in situ component of human mucosal melanoma. The spectrum of canine melanocytic neoplasia includes benign lesions with some analogy to nevi, as well as invasive primary melanoma, and widespread metastasis. Growing evidence of distinct subtypes in humans, differing in somatic and predisposing germ-line genetic alterations, cell of origin, epidemiology, relationship to ultraviolet radiation and progression from benign to malignant tumors, may also exist in dogs. Canine and human mucosal melanomas appear to harbor BRAF, NRAS, and c-kit mutations uncommonly, compared with human cutaneous melanomas, although both species share AKT and MAPK signaling activation. We conclude that there is significant overlap in the clinical and histopathological features of canine and human mucosal melanomas. This represents opportunity to explore canine oral cavity melanoma as a preclinical model