Shared Information -- New Insights and Problems in Decomposing Information in Complex Systems

How can the information that a set ${X_{1},...,X_{n}}$ of random variables contains about another random variable $S$ be decomposed? To what extent do different subgroups provide the same, i.e. shared or redundant, information, carry unique information or interact for the emergence of synergistic information? Recently Williams and Beer proposed such a decomposition based on natural properties for shared information. While these properties fix the structure of the decomposition, they do not uniquely specify the values of the different terms. Therefore, we investigate additional properties such as strong symmetry and left monotonicity. We find that strong symmetry is incompatible with the properties proposed by Williams and Beer. Although left monotonicity is a very natural property for an information measure it is not fulfilled by any of the proposed measures. We also study a geometric framework for information decompositions and ask whether it is possible to represent shared information by a family of posterior distributions. Finally, we draw connections to the notions of shared knowledge and common knowledge in game theory. While many people believe that independent variables cannot share information, we show that in game theory independent agents can have shared knowledge, but not common knowledge. We conclude that intuition and heuristic arguments do not suffice when arguing about information.Comment: 20 page

Why do Particle Clouds Generate Electric Charges?

Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, because it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. Here, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains in the presence of an electric field, and we confirm the model's predictions using discrete-element simulations and a tabletop granular experiment

Inhibition of human cytomegalovirus replication by interferon alpha can involve multiple anti-viral factors

The shortcomings of current direct-acting anti-viral therapy against human cytomegalovirus (HCMV) has led to interest in host-directed therapy. Here we re-examine the use of interferon proteins to inhibit HCMV replication utilizing both high and low passage strains of HCMV. Pre-treatment of cells with interferon alpha (IFNα) was required for robust and prolonged inhibition of both low and high passage HCMV strains, with no obvious toxicity, and was associated with an increased anti-viral state in HCMV-infected cells. Pre-treatment of cells with IFNα led to poor expression of HCMV immediate-early proteins from both high and low passage strains, which was associated with the presence of the anti-viral factor SUMO-PML. Inhibition of HCMV replication in the presence of IFNα involving ZAP proteins was HCMV strain-dependent, wherein a high passage HCMV strain was obviously restricted by ZAP and a low passage strain was not. This suggested that strain-specific combinations of anti-viral factors were involved in inhibition of HCMV replication in the presence of IFNα. Overall, this work further supports the development of strategies involving IFNα that may be useful to inhibit HCMV replication and highlights the complexity of the anti-viral response to HCMV in the presence of IFNα

The transition into veterinary practice: Opinions of recent graduates and final year students

Background The transition from veterinary student to member of the veterinary profession is known to be challenging. This study aimed to determine and compare the opinions of final year veterinary students and recent graduates on graduate attributes that ease this transition. Methods The study was carried out across 3 veterinary schools in the United Kingdom. Paper based or electronic surveys were used. Final year students in the 3 schools were surveyed either electronically (school A) or on paper (schools B and C). Student cohort sizes were 112, 227 and 102 respectively. Recent graduates were contacted either at a reunion event (school A) or electronically from database records (school B and school C). Cohort sizes of contacted graduates were 80, 175 and 91 respectively. Respondents were asked to rate 42 individual attributes on a 5 point Likert scale. Focus groups with final year students and recent graduates and telephone interviews with recent graduates were carried out. Data were analysed by two researchers through a combination of manual coding and thematic analysis. Data were grouped into broad themes then sorted into narrower themes. Data were then searched for counter examples. Results Response rates for final year students were 34% (school A), 36% (school B) and 40% (school C). Response rates for recent graduates were 56% (school A), 20% (school B) and 11% (school C). There was a high level of agreement between the cohorts with respect to communication skills, problem solving and decision making skills, recognition of own limitations and the ability to cope with pressure all rated unanimously important or very important. Business acumen, knowledge of veterinary practice management and research skills were the 3 attributes ranked at the bottom of the list. Nine attributes were identified with a significantly different (p < 0.05) ranking between the cohorts. Final year students ranked veterinary clinical knowledge, knowledge of veterinary public health and zoonotic issues, veterinary legislation and veterinary practice management, commitment to continuing professional development and ability to evaluate information higher than recent graduates. Recent graduates ranked the attributes of integrity, friendliness and compassion higher than final year students. Conclusions Recent graduates and final year students rate highly the attributes which help foster the client/veterinarian relationship. Recent graduates reflect that a focus on knowledge based attributes is less important once in practice when compared to final year. The study confirms the importance to recent graduates and final year students of attributes considered as non-technical in the transition to working in the veterinary profession

Periodic eclipses of the young star PDS 110 discovered with WASP and KELT photometry

We report the discovery of eclipses by circumstellar disc material associated with the young star PDS 110 in the Ori OB1a association using the SuperWASP and Kilodegree Extremely Little Telescope surveys. PDS 110 (HD 290380, IRAS 05209-0107) is a rare Fe/Ge-type star, an similar to 10 Myr-old accreting intermediate-mass star showing strong infrared excess (L-IR/L-bol similar or equal to 0.25). Two extremely similar eclipses with a depth of 30 per cent and duration similar to 25 d were observed in 2008 November and 2011 January. We interpret the eclipses as caused by the same structure with an orbital period of 808 +/- 2 d. Shearing over a single orbit rules out diffuse dust clumps as the cause, favouring the hypothesis of a companion at similar to 2 au. The characteristics of the eclipses are consistent with transits by an unseen low-mass (1.8-70M(Jup)) planet or brown dwarf with a circumsecondary disc of diameter similar to 0.3 au. The next eclipse event is predicted to take place in 2017 September and could be monitored by amateur and professional observatories across the world

Evidence for an excess of B -> D(*) Tau Nu decays

Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the format of Figure 2 and included the effect of the change of the Tau polarization due to the charged Higg

Search for the decay modes D^0 → e^+e^-, D^0 → μ^+μ^-, and D^0 → e^±μ∓

We present searches for the rare decay modes D^0→e^+e^-, D^0→μ^+μ^-, and D^0→e^±μ^∓ in continuum e^+e^-→cc events recorded by the BABAR detector in a data sample that corresponds to an integrated luminosity of 468  fb^(-1). These decays are highly Glashow–Iliopoulos–Maiani suppressed but may be enhanced in several extensions of the standard model. Our observed event yields are consistent with the expected backgrounds. An excess is seen in the D^0→μ^+μ^- channel, although the observed yield is consistent with an upward background fluctuation at the 5% level. Using the Feldman–Cousins method, we set the following 90% confidence level intervals on the branching fractions: B(D^0→e^+e^-)<1.7×10^(-7), B(D^0→μ^+μ^-) within [0.6,8.1]×10^(-7), and B(D^0→e^±μ^∓)<3.3×10^(-7)

Idiopathic membranous nephropathy in pediatric patients: presentation, response to therapy, and long-term outcome

<p>Abstract</p> <p>Background</p> <p>Idiopathic membranous nephropathy (IMN) is one of the most common causes of primary nephrotic syndrome in adults. However, it is a relatively rare entity in the pediatric population and there is a paucity of data about the incidence, prognosis, and optimal treatment of IMN in children and adolescents. We conducted this study to evaluate pediatric patients with IMN in order to clarify the presentation, response to therapy, and clinical outcome.</p> <p>Methods</p> <p>A retrospective chart review was performed on patients identified with biopsy-proven IMN between 1988–2005. Patients with systemic lupus erythematosus or hepatitis-related lesions were excluded. The following data were tabulated: age, gender, ethnicity, presenting clinical and laboratory findings, proteinuria in a first morning urine specimen, estimated glomerular filtration rate (GFR_e), histopathology, type and duration of treatment, and clinical status at final evaluation.</p> <p>Results</p> <p>13 cases of IMN were identified out of 460 renal biopsies performed for evaluation of primary kidney disease during the study interval. Mean age was 9.6 ± 4.6, gender 6 M:7 F, ethnicity 8 W:2 B:3 H. At the initial visit hematuria was present in 9 patients, edema in 5, nephrotic-range proteinuria in 5, and hypertension in 3. Mean urinary protein:creatinine ratio 3.3 ± 2.5 and all patients had a normal GFR_e. Classic glomerular findings of IMN were seen in all renal specimens, with concomitant interstitial changes in 2 cases. Treatment included an angiotensin converting enzyme inhibitor or angiotensin receptor blocker in 11 cases. Most patients were also given immunosuppressive medications – prednisone in 10, a calcineurin inhibitor in 5, and mycophenolate mofetil or azathioprine in 3 patients. At the last follow-up, 42 ± 35 months after the diagnostic biopsy, 7 children were hypertensive and the urine protein:creatinine ratio was 2.3 ± 3.1. The mean GFR_ewas 127 ± 57 mL/min/m². Three patients had Chronic Kidney Disease Stage 3, all of whom were also hypertensive.</p> <p>Conclusion</p> <p>IMN is a rare but serious glomerulopathy in pediatrics. We estimate that it accounts for approximately 3% of renal biopsies. Long-term prognosis is guarded because approximately 50% of patients may have evidence of progressive kidney disease.</p

Energy Reallocation to Breeding Performance through Improved Nest Building in Laboratory Mice.

Mice are housed at temperatures (20-26°C) that increase their basal metabolic rates and impose high energy demands to maintain core temperatures. Therefore, energy must be reallocated from other biological processes to increase heat production to offset heat loss. Supplying laboratory mice with nesting material may provide sufficient insulation to reduce heat loss and improve both feed conversion and breeding performance. Naïve C57BL/6, BALB/c, and CD-1breeding pairs were provided with bedding alone, or bedding supplemented with either 8g of Enviro-Dri, 8g of Nestlets, for 6 months. Mice provided with either nesting material built more dome-like nests than controls. Nesting material improved feed efficiency per pup weaned as well as pup weaning weight. The breeding index (pups weaned/dam/week) was higher when either nesting material was provided. Thus, the sparing of energy for thermoregulation of mice given additional nesting material may have been responsible for the improved breeding and growth of offspring

Mouse Ribosomal RNA Genes Contain Multiple Differentially Regulated Variants

Previous cytogenetic studies suggest that various rDNA chromosomal loci are not equally active in different cell types. Consistent with this variability, rDNA polymorphism is well documented in human and mouse. However, attempts to identify molecularly rDNA variant types, which are regulated individually (i.e., independent of other rDNA variants) and tissue-specifically, have not been successful. We report here the molecular cloning and characterization of seven mouse rDNA variants (v-rDNA). The identification of these v-rDNAs was based on restriction fragment length polymorphisms (RFLPs), which are conserved among individuals and mouse strains. The total copy number of the identified variants is less than 100 and the copy number of each individual variant ranges from 4 to 15. Sequence analysis of the cloned v-rDNA identified variant-specific single nucleotide polymorphisms (SNPs) in the transcribed region. These SNPs were used to develop a set of variant-specific PCR assays, which permitted analysis of the v-rDNAs' expression profiles in various tissues. These profiles show that three v-rDNAs are expressed in all tissues (constitutively active), two are expressed in some tissues (selectively active), and two are not expressed (silent). These expression profiles were observed in six individuals from three mouse strains, suggesting the pattern is not randomly determined. Thus, the mouse rDNA array likely consists of genetically distinct variants, and some are regulated tissue-specifically. Our results provide the first molecular evidence for cell-type-specific regulation of a subset of rDNA