On Vague Computers

Vagueness is something everyone is familiar with. In fact, most people think that vagueness is closely related to language and exists only there. However, vagueness is a property of the physical world. Quantum computers harness superposition and entanglement to perform their computational tasks. Both superposition and entanglement are vague processes. Thus quantum computers, which process exact data without "exploiting" vagueness, are actually vague computers

The reconstructed Indonesian warm pool sea surface temperatures from tree rings and corals: Linkages to Asian monsoon drought and El Niño–Southern Oscillation

[ 1] The west Pacific warm pool is the heat engine for the globe's climate system. Its vast moisture and heat exchange profoundly impact conditions in the tropics and higher latitudes. Here, September - November sea surface temperature (SST) variability is reconstructed for the warm pool region (15 degrees S - 5 degrees N, 110 - 160 degrees E) surrounding Indonesia using annually resolved teak ring width and coral delta O-18 records. The reconstruction dates from A. D. 1782 - 1992 and accounts for 52% of the SST variance over the most replicated period. Significant correlations are found with El Nino - Southern Oscillation (ENSO) and monsoon indices at interannual to decadal frequency bands. Negative reconstructed SST anomalies coincide with major volcanic eruptions, while other noteworthy extremes are at times synchronous with Indian and Indonesian monsoon drought, particularly during major warm ENSO episodes. While the reconstruction adds to the sparse network of proxy reconstructions available for the tropical Indo-Pacific, additional proxies are needed to clarify how warm pool dynamics have interacted with global climate in past centuries to millennia.</p

Population stability: regulating size in the presence of an adversary

We introduce a new coordination problem in distributed computing that we call the population stability problem. A system of agents each with limited memory and communication, as well as the ability to replicate and self-destruct, is subjected to attacks by a worst-case adversary that can at a bounded rate (1) delete agents chosen arbitrarily and (2) insert additional agents with arbitrary initial state into the system. The goal is perpetually to maintain a population whose size is within a constant factor of the target size $N$. The problem is inspired by the ability of complex biological systems composed of a multitude of memory-limited individual cells to maintain a stable population size in an adverse environment. Such biological mechanisms allow organisms to heal after trauma or to recover from excessive cell proliferation caused by inflammation, disease, or normal development. We present a population stability protocol in a communication model that is a synchronous variant of the population model of Angluin et al. In each round, pairs of agents selected at random meet and exchange messages, where at least a constant fraction of agents is matched in each round. Our protocol uses three-bit messages and $\omega(\log^2 N)$ states per agent. We emphasize that our protocol can handle an adversary that can both insert and delete agents, a setting in which existing approximate counting techniques do not seem to apply. The protocol relies on a novel coloring strategy in which the population size is encoded in the variance of the distribution of colors. Individual agents can locally obtain a weak estimate of the population size by sampling from the distribution, and make individual decisions that robustly maintain a stable global population size

Audit of failure rate of sulfadoxine/pyrimethamine combined with chloroquine to treat falciparum malaria at single fourteen-day follow-up

Objective. To assess the failure rate of the present first line treatment regime for uncomplicated falciparum malaria of sulfadoxine/pyrimethamine combined with chloroquine. Design. A before-after study1 Setting. Ndumo Clinic, Ingwavuma District, South Africa, October 2000 Study Group. 55 patients presenting to Ndumo clinic with uncomplicated malaria and malaria trophozoites visible on thin film. Main outcome measures:Trophozoite count on thick film at day 14. Results. 15 out of 37 patients who returned for follow-up still had trophozoites on thick film. Symptoms of most patients at day 0 and day 14 were mild, parasite counts before and after treatment were low, and trophozoites were atypical. Conclusions. There appears to be an unacceptably high day 14 failure rate with the combination of sulfadoxine/pyrimethamine and chloroquine.The mildness of symptoms, low parasite counts and atypical trophozoites suggest immunity to falciparum malaria amongst the local population. With few antimalarials to chose from, the difficult question as to future treatment of uncomplicated malaria arises. Keywords: Falciparum malaria, chloroquine, sulfadoxine, pyrimethamine SA Fam Prac Vol.25(3) 2002: 4-

A Robust AFPTAS for Online Bin Packing with Polynomial Migration

In this paper we develop general LP and ILP techniques to find an approximate solution with improved objective value close to an existing solution. The task of improving an approximate solution is closely related to a classical theorem of Cook et al. in the sensitivity analysis for LPs and ILPs. This result is often applied in designing robust algorithms for online problems. We apply our new techniques to the online bin packing problem, where it is allowed to reassign a certain number of items, measured by the migration factor. The migration factor is defined by the total size of reassigned items divided by the size of the arriving item. We obtain a robust asymptotic fully polynomial time approximation scheme (AFPTAS) for the online bin packing problem with migration factor bounded by a polynomial in $\frac{1}{\epsilon}$. This answers an open question stated by Epstein and Levin in the affirmative. As a byproduct we prove an approximate variant of the sensitivity theorem by Cook at el. for linear programs

Characterising the burden of chronic kidney disease among people with type 2 diabetes in England: a cohort study using the Clinical Practice Research Datalink

Objectives To describe prevalence of chronic kidney disease (CKD), demographic and clinical characteristics, treatment patterns and rates of cardiovascular and renal complications for patients with type 2 diabetes (T2D) treated in routine clinical care. Design Repeat cross-sectional study (6 monthly cross-sections) and cohort study from 1 January 2017 to 31 December 2019. Setting Primary care data from English practices contributing to the UK Clinical Practice Research Datalink linked to Hospital Episode Statistics and Office for National Statistics mortality data. Participants Patients with T2D aged >18 years, at least one year of registration data. Primary and secondary outcomes Primary outcome was prevalence of CKD defined as chronic kidney disease epidemiology collaboration (CKD-EPI) estimated glomerular filtration rate <60 mL/min/1.73 m2, and/or urinary albumin creatinine ratio ≥3 mg/mmol in the past 24 months. Secondary outcomes were prescriptions of medications of interest and clinical and demographic characteristics in the past 3 months. In the cohort study rates of renal and cardiovascular complications, all-cause mortality and hospitalisations over the study period were compared among those with and without CKD. Results There were 574 190 eligible patients with T2D as of 1 January 2017 and 664 296 as of 31 December 2019. Estimated prevalence of CKD across the study period was stable at approximately 30%. Medication use was stable over time in people with CKD and T2D, with low use of steroidal mineralocorticoid receptor antagonists (approximately 4.5% across all time points) and a low use but steady increase in use of sodium-glucose co-transporter-2 inhibitors (from 2.6% to 6.2%). Rates of all complications were higher in those with CKD at the start of the study period, with increasing rates, with increased severity of CKD, heart failure and albuminuria. Conclusions The burden of CKD in patients with T2D is high and associated with substantially increased rates of complications particularly in those with comorbid heart failure

A Upf3b-mutant mouse model with behavioral and neurogenesis defects.

Nonsense-mediated RNA decay (NMD) is a highly conserved and selective RNA degradation pathway that acts on RNAs terminating their reading frames in specific contexts. NMD is regulated in a tissue-specific and developmentally controlled manner, raising the possibility that it influences developmental events. Indeed, loss or depletion of NMD factors have been shown to disrupt developmental events in organisms spanning the phylogenetic scale. In humans, mutations in the NMD factor gene, UPF3B, cause intellectual disability (ID) and are strongly associated with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCZ). Here, we report the generation and characterization of mice harboring a null Upf3b allele. These Upf3b-null mice exhibit deficits in fear-conditioned learning, but not spatial learning. Upf3b-null mice also have a profound defect in prepulse inhibition (PPI), a measure of sensorimotor gating commonly deficient in individuals with SCZ and other brain disorders. Consistent with both their PPI and learning defects, cortical pyramidal neurons from Upf3b-null mice display deficient dendritic spine maturation in vivo. In addition, neural stem cells from Upf3b-null mice have impaired ability to undergo differentiation and require prolonged culture to give rise to functional neurons with electrical activity. RNA sequencing (RNAseq) analysis of the frontal cortex identified UPF3B-regulated RNAs, including direct NMD target transcripts encoding proteins with known functions in neural differentiation, maturation and disease. We suggest Upf3b-null mice serve as a novel model system to decipher cellular and molecular defects underlying ID and neurodevelopmental disorders

Monsoon drought over Java, Indonesia, during the past two centuries

Monsoon droughts, which often coincide with El Nino warm events, can have profound impacts on the populations of Southeast Asia. Improved understanding and prediction of such events can be aided by high-resolution proxy climate records, but these are scarce for the tropics. Here we reconstruct the boreal autumn (October-November) Palmer Drought Severity Index (PDSI) for Java, Indonesia (1787-1988). This reconstruction is based on nine ring-width chronologies derived from living teak trees growing on the islands of Java and Sulawesi, and one coral delta O-18 series from Lombok. The PDSI reconstruction correlates significantly with El Nino-Southern Oscillation (ENSO)-related sea surface temperatures and other historical and instrumental records of tropical climate, reflecting the strong coupling between the climate of Indonesia and the large scale tropical Indo-Pacific climate system.</p

Modelling glacial lake outburst flood impacts in the Bolivian Andes

The Bolivian Andes have experienced sustained and widespread glacier mass loss in recent decades. Glacier recession has been accompanied by the development of proglacial lakes, which pose a glacial lake outburst flood (GLOF) risk to downstream communities and infrastructure. Previous research has identified three potentially dangerous glacial lakes in the Bolivian Andes, but no attempt has yet been made to model GLOF inundation downstream from these lakes. We generated 2-m resolution DEMs from stereo and tri-stereo SPOT 6/7 satellite images to drive a hydrodynamic model of GLOF flow (HEC-RAS 5.0.3). The model was tested against field observations of a 2009 GLOF from Keara, in the Cordillera Apolobamba, and was shown to reproduce realistic flood depths and inundation. The model was then used to model GLOFs from Pelechuco lake (Cordillera Apolobamba) and Laguna Arkhata and Laguna Glaciar (Cordillera Real). In total, six villages could be affected by GLOFs if all three lakes burst. For sensitivity analysis, we ran the model for three scenarios (pessimistic, intermediate, optimistic), which give a range of ~ 1100 to ~ 2200 people affected by flooding; between ~ 800 and ~ 2100 people could be exposed to floods with a flow depth ≥ 2 m, which could be life threatening and cause a significant damage to infrastructure. We suggest that Laguna Arkhata and Pelechuco lake represent the greatest risk due to the higher numbers of people who live in the potential flow paths, and hence, these two glacial lakes should be a priority for risk managers