4,426 research outputs found
A population-based microbial oscillator
Genetic oscillators are a major theme of interest in the emerging field of
synthetic biology. Until recently, most work has been carried out using
intra-cellular oscillators, but this approach restricts the broader
applicability of such systems. Motivated by a desire to develop large-scale,
spatially-distributed cell-based computational systems, we present an initial
design for a population-level oscillator which uses three different bacterial
strains. Our system is based on the client-server model familiar to computer
science, and uses quorum sensing for communication between nodes. We present
the results of extensive in silico simulation tests, which confirm that our
design is both feasible and robust.Comment: Submitte
Centralized and distributed cognitive task processing in the human connectome
A key question in modern neuroscience is how cognitive changes in a human
brain can be quantified and captured by functional connectomes (FC) . A
systematic approach to measure pairwise functional distance at different brain
states is lacking. This would provide a straight-forward way to quantify
differences in cognitive processing across tasks; also, it would help in
relating these differences in task-based FCs to the underlying structural
network. Here we propose a framework, based on the concept of Jensen-Shannon
divergence, to map the task-rest connectivity distance between tasks and
resting-state FC. We show how this information theoretical measure allows for
quantifying connectivity changes in distributed and centralized processing in
functional networks. We study resting-state and seven tasks from the Human
Connectome Project dataset to obtain the most distant links across tasks. We
investigate how these changes are associated to different functional brain
networks, and use the proposed measure to infer changes in the information
processing regimes. Furthermore, we show how the FC distance from resting state
is shaped by structural connectivity, and to what extent this relationship
depends on the task. This framework provides a well grounded mathematical
quantification of connectivity changes associated to cognitive processing in
large-scale brain networks.Comment: 22 pages main, 6 pages supplementary, 6 figures, 5 supplementary
figures, 1 table, 1 supplementary table. arXiv admin note: text overlap with
arXiv:1710.0219
The determinants of rising informality in Brazil : Evidence from gross worker flows
This paper studies gross worker flows to explain the rising informality in Brazilian metropolitan labor markets from 1983 to 2002. This period covers two economic cycles, several stabilization plans, a far-reaching trade liberalization, and changes in labor legislation through the Constitutional reform of 1988. First, focusing on cyclical patterns, the authors confirm that for Brazil, the patterns of worker transitions between formality and informality correspond primarily to the job-to-job dynamics observed in the United States, and not to the traditional idea of the informal queuing for jobs in a segmented market. However, the analysis also confirms distinct cyclical patterns of job finding and separation rates that lead to the informal sector absorbing more labor during downturns. Second, focusing on secular movements in gross flows and the volatility of flows, the paper finds the rise in informality to be driven primarily by a reduction in job finding rates in the formal sector. A small fraction of this is driven by trade liberalization, and the remainder seems driven by rising labor costs and reduced flexibility arising from Constitutional reform.Labor Markets,Labor Policies,Population Policies,,Health Monitoring&Evaluation
Getting realabout inequality : evidence from Brazil, Colombia, Mexico, and Peru
Consumption baskets vary across households and inflation rates vary across goods. As a result, standard consumer price index (CPI) inflation may provide a misleading measure of the inflation actually faced by poor households, more so the more unequal the distribution of aggregate consumption across households. Likewise, changes in observed nominal consumption inequality may be very different from those in true inequality, that is, that measured using household-specific CPIs. The authors explore empirically these issues using household data covering nine episodes from four Latin American countries (Brazil, Colombia, Mexico, and Peru). They find that in these countries standard CPI inflation typically reflects the inflation rate faced by a rich consumer located in the 80 to 90 percentile of the distribution of consumption expenditure. In most episodes the authors also find that inflation was anti-rich-that is, the inflation faced by the richest consumers was higher than the inflation faced by the poorest consumers. As a result of this bias, the observed increases in nominal inequality generally exceed the actual changes in real inequality. These results are robust to correcting for quality change bias in the CPI, to the use of alternative price indices, and to the use of alternative inequality measures.Markets and Market Access,Economic Theory&Research,Access to Markets,Inequality,Consumption
Fiscal redistribution and income inequality in Latin America
Income inequality in Latin America ranks among the highest in the world. It can be traced back to the unequal distribution of assets (especially land and education) in the region. But the extent to which asset inequality translates into income inequality depends on the redistributive capacity of the state. This paper documents the performance of Latin American fiscal systems from the perspective of income redistribution using newly-available information on the incidence of taxes and transfers across the region. The findings indicate that: (i) the differences in income inequality before taxes and transfers between Latin America and Western Europe are much more modest than those after taxes and transfers; (ii) the key reason is that, in contrast with industrial countries, in most Latin American countries the fiscal system is of little help in reducing income inequality; and (iii) in countries where fiscal redistribution is significant, it is achieved mostly through transfers rather than taxes. These facts stress the need for fiscal reforms across the region to further the goal of social equity. However, different countries need to place different relative emphasis on raising tax collection, restructuring the tax system, and improving the targeting of expenditures.Taxation&Subsidies,Emerging Markets,Debt Markets,Economic Theory&Research,Poverty Impact Evaluation
Neural indicators of fatigue in chronic diseases : A systematic review of MRI studies
The authors would like to thank the Sir Jules Thorn Charitable Trust for their financial support.Peer reviewedPublisher PD
PENERAPAN PRINSIP RESTORATIVE JUSTICE PADA TERPIDANA ANAK
Tujuan penelitian adalah untuk mengetahui bagaimana proses peradilan terhadap anak yang melakukanĂÂ tindak pidana dan bagaiamana penerapan prinsip restorative justice pada terpidana anak di mana dengan metode penelitian hukum normatif disimnpulkan bahwa: 1. Proses peradilan terhadap anak adalah sebagai berikut: Sidang dilaksanakan dengan cara tertutup dan pembacaan putusan dilaksanakan terbuka untuk umum; Penyidik, penuntut umum, hakim dan penasihat hukum dalam melaksanakan fungsinya sebagai penegak hukum tidak menggunakan pakaian dinas atau bertoga; Sidang dipimpin oleh hakim tunggal, kecuali dalam hal ditentukan lain;ĂÂ Hakim yang mengadili anak adalah hakim khusus diutamakan hakim wanita yang memiliki pengetahuan masalah kejiwaan anak; Sidang diadakan pada hari khusus; Selama dalam persidangan, anak harus didampingi orang tua; Tidak boleh diliput oleh wartawan; Sebelum dibacakan tuntutan jaksa dan putusan hakim, harus terlebih dahulu dibacakan laporan petugas sosial yang ditugaskan oleh pengadilan untuk meneliti perilaku dan kondisi anak tersebut. 2. Penerapan prinsip restorative justice pada terpidana anak atau anak pelaku tindak pidana sangatlah diperlukan untuk perbaikan atau penggantian kerugian yang diderita oleh korban, pengakuan pelaku terhadap luka yang diderita oleh masyarakat akibat tindakannya, konsiliasi dan rekonsiliasi pelaku, korban dan masyarakat. Karena tujuan dari restorasi keadilan adalah merestorasi kesejahteraan masyarakat, memperbaiki manusia sebagai anggota masyarakat dengan cara menghadapkan anak sebagai pelaku berupa pertanggungjawaban kepada korban atas tindakannya.Kata kunci: restorative justice; anak
Assortative Matching at the Top of the Distribution: Evidence from the Worldâs Most Exclusive Marriage Market
Using novel data on peerage marriages in Britain, I find that low search costs and marriage-market segregation can generate sorting. Peers courted in the London Season, a matching technology introducing aristocratic bachelors to debutantes. When Queen Victoria went into mourning for her husband, the Season was interrupted (1861â1863), raising search costs and reducing market segregation. I exploit exogenous variation in women's probability to marry during the interruption from their age in 1861. The interruption increased peer-commoner intermarriage by 40 percent and reduced sorting along landed wealth by 30 percent. Eventually, this reduced peers' political power and affected public policy in late nineteenth-century England.publishedVersio
Synthesis and Characterization of Transition Metal Pincer Complexes on a Silica Polyamine Composites for Catalytic Applications
There are two main parts of this dissertation: (i) Investigation of the most efficient method for loading and synthesizing catalytically active pincer metal complexes on a silica polyamine composite, BP-1, and (ii) study of the catalytic activity of the immobilized pincer complexes on the BP-1 surface.
Three methods were investigated to immobilize pincer complexes on BP-1 using PONOP pincer complexes of Ru, Rh, Ni and Pd. Method 1, appeared to be the most suitable and effective process to load the pincer complexes: the immobilization proceeded by a two-step Mannich reaction with the addition of preassembled pincer metal complexes to BP-1. The complexes on BP-1 were characterized by solid state NMR, FT-IR, elemental analysis, and metal digestion studies. The model solution experiments between pincer complexes and n-butylamine revealed electrophilic substitution in both the meta- and para-position of pyridine ring of the pincer complexes by Mannich intermediate.
The catalytic reactivity of immobilized (PNN)RuH(Cl)(CO) and (PONOP)RuH(Cl)(CO) on BP-1 was studied in the dehydrogenative coupling of alcohols to esters and H2 reactions. Moderate to good ester yields were realized with both immobilized systems without using any base and in the presence of KOH. The homogeneous reactions required a base for catalysis. The amine functionality on BP-1 functioned as a base to generate active pincer catalyst on the BP-1 surface. Both immobilized catalysts were recycled for multiple alcohol reaction cycles. BP-1-Ru-PNN showed alcohol conversions up to five cycles, whereas BP-1-Ru-PONOP was found to be survived up to the fourth catalytic cycle. Four control experiments were carried out using alcohol and both of the immobilized systems. The results revealed the heterogeneity of alcohol catalysis by both BP-1-Ru-PNN and BP-1-Ru-PONOP systems. The composite catalysts were also tested in amide formation reactions from amines and alcohols. Instead of generating amides, the imines formations were realized by the coupling of amines in both cases.
This study opened a new catalytic method for important metal pincer complexes in their known catalytic reactions where the requirement of using a base is eliminated for the catalysis by the utilization of a solid support with basic functionality. It also suggested different immobilization approaches which will save the relatively expensive pincer catalysts for multiple uses in catalysis
- âŠ