304 research outputs found
Review : Profil Hybrid Membrane Dalam Proses Reduksi Air Limbah
Frekuensi penggunaan air sangat tinggi seiring dengan perkembangan teknologi dan pertumbuhan jumlah penduduk. Peningkatan standar hidup manusia yang semakin tinggi menimbulkan permasalahan lingkungan terkait dengan kualitas air akibat bahan kimia, nutrisi, lindi, tumpahan minyak, pembuangan limbah bahan berbahaya, serta penggunaan bahan dispossable dan non-biodegradable. Perkembangan sumber daya teknologi menghasilkan suatu revolusi sehingga menghasilkan lebih banyak bahan dan senyawa kimia. sejumlah senyawa yang diidentifikasi memiliki ancaman potensial terhadap organisme lingkungan hidup. Tujuan penelitian ini adalah mengidentifikasi teknik pengolahan air limbah dengan menggabungkan dua sifat membran dalam mereduksi air limbah. Metode yang digunakan adalah review dari beberapa sumber pustaka dengan melakukan studi literatur terdahulu terhadap beberapa penelitian yang pernah dilakukan. Kesimpulan dari penelitian menghasilkan bahwa teknologi membran sebagai salah satu instalasi unit pengolahan limbah perkembangan dan kemajuannya sangat menjanjikan dan banyak dilakukan dalam proses dengan prinsip pemisahan dan pemurnian air. Teknologi membran bisa menjadi solusi dalam pengolahan air limbah, seiring dengan perkembangannya membran dapat dikombinasikan (Hybrid Process) dengan menggunakan berbagai jenis membrane yaitu Ultrafiltrasi, Mikrofiltrasi, Nanofiltrasi dan Reverse Osmosis, akan tetapi harus diperhatikan kondisi operasional dari proses tersebut
A simple mean field model for social interactions: dynamics, fluctuations, criticality
We study the dynamics of a spin-flip model with a mean field interaction. The
system is non reversible, spacially inhomogeneous, and it is designed to model
social interactions. We obtain the limiting behavior of the empirical averages
in the limit of infinitely many interacting individuals, and show that phase
transition occurs. Then, after having obtained the dynamics of normal
fluctuations around this limit, we analize long time fluctuations for critical
values of the parameters. We show that random inhomogeneities produce critical
fluctuations at a shorter time scale compared to the homogeneous system.Comment: 37 pages, 2 figure
Certifying forest-based ecosystem services: results from the world-first application of the FSC ecosystem service procedure in Italy
In recent years, several mechanisms have been put in practice to value forest-based ecosystem services in order to maintain or enhance their provision. Mechanisms range from more traditional - e.g. regulation of land use, taxes and subsidies - to more innovative market-based ones such as Payments for Ecosystem Services (PES). More recently, the use of voluntary third-party forest certification schemes based on standards and procedures specifically aimed at considering the provision of ecosystem services has gained interests. Certification schemes have already been established for specific ecosystem services, in particular focusing on carbon, in some cases including biodiversity conservation as a co-benefit. The Forest Stewardship Council\uae (FSC) is currently the only scheme promoting the certification of multiple ecosystem services by demonstrating the positive impacts of FSC-certified forest management practices on five regulating and cultural services. A dedicated procedure has been developed, that allows the assessment of the impact of forest management on carbon sequestration and storage, biodiversity conservation, watershed services, soil conservation and recreational services, by means of specific methodologies and indicators. We critically analyzed the world-first application of the FSC ecosystem services certification procedure with reference to the forest certification group Waldplus and Associazione Forestale di Pianura (Lowland Forest Association) in northern Italy. The case study includes 1,043 hectares of different forest types, from semi-natural productive forests to conservation forests, traditionally managed to deliver multiple benefits. Our objective is to give insights that could inform and improve future developments in the field of certification, promotion and marketing of ecosystem services
Systemic Risk and Default Clustering for Large Financial Systems
As it is known in the finance risk and macroeconomics literature,
risk-sharing in large portfolios may increase the probability of creation of
default clusters and of systemic risk. We review recent developments on
mathematical and computational tools for the quantification of such phenomena.
Limiting analysis such as law of large numbers and central limit theorems allow
to approximate the distribution in large systems and study quantities such as
the loss distribution in large portfolios. Large deviations analysis allow us
to study the tail of the loss distribution and to identify pathways to default
clustering. Sensitivity analysis allows to understand the most likely ways in
which different effects, such as contagion and systematic risks, combine to
lead to large default rates. Such results could give useful insights into how
to optimally safeguard against such events.Comment: in Large Deviations and Asymptotic Methods in Finance, (Editors: P.
Friz, J. Gatheral, A. Gulisashvili, A. Jacqier, J. Teichmann) , Springer
Proceedings in Mathematics and Statistics, Vol. 110 2015
A self-configuring control system for storage and computing departments at INFN-CNAF Tierl
The storage and farming departments at the INFN-CNAF Tier1[1] manage approximately thousands of computing nodes and several hundreds of servers that provides access to the disk and tape storage. In particular, the storage server machines should provide the following services: an efficient access to about 15 petabytes of disk space with different cluster of GPFS file system, the data transfers between LHC Tiers sites (Tier0, Tier1 and Tier2) via GridFTP cluster and Xrootd protocol and finally the writing and reading data operations on magnetic tape backend. One of the most important and essential point in order to get a reliable service is a control system that can warn if problems arise and which is able to perform automatic recovery operations in case of service interruptions or major failures. Moreover, during daily operations the configurations can change, i.e. if the GPFS cluster nodes roles can be modified and therefore the obsolete nodes must be removed from the control system production, and the new servers should be added to the ones that are already present. The manual management of all these changes is an operation that can be somewhat difficult in case of several changes, it can also take a long time and is easily subject to human error or misconfiguration. For these reasons we have developed a control system with the feature of self-configure itself if any change occurs. Currently, this system has been in production for about a year at the INFN-CNAF Tier1 with good results and hardly any major drawback. There are three major key points in this system. The first is a software configurator service (e.g. Quattor or Puppet) for the servers machines that we want to monitor with the control system; this service must ensure the presence of appropriate sensors and custom scripts on the nodes to check and should be able to install and update software packages on them. The second key element is a database containing information, according to a suitable format, on all the machines in production and able to provide for each of them the principal information such as the type of hardware, the network switch to which the machine is connected, if the machine is real (physical) or virtual, the possible hypervisor to which it belongs and so on. The last key point is a control system software (in our implementation we choose the Nagios software), capable of assessing the status of the servers and services, and that can attempt to restore the working state, restart or inhibit software services and send suitable alarm messages to the site administrators. The integration of these three elements was made by appropriate scripts and custom implementation that allow the self-configuration of the system according to a decisional logic and the whole combination of all the above-mentioned components will be deeply discussed in this paper
Short-time Gibbsianness for Infinite-dimensional Diffusions with Space-Time Interaction
We consider a class of infinite-dimensional diffusions where the interaction
between the components is both spatial and temporal. We start the system from a
Gibbs measure with finite-range uniformly bounded interaction. Under suitable
conditions on the drift, we prove that there exists such that the
distribution at time is a Gibbs measure with absolutely summable
interaction. The main tool is a cluster expansion of both the initial
interaction and certain time-reversed Girsanov factors coming from the
dynamics
Reproducing the City of London’s institutional landscape: the role of education and the learning of situated practices by early career elites
In this paper we argue that postgraduate education forms an important, but hitherto neglected, element in the distinctive institutional landscape of the City of London.
In particular, and drawing on research into early-career financial and legal elites in the City, we show how postgraduate education tailored to the demands of employers within London plays an important role in indoctrinating early-career elites into situated, Cityspecific,
working practices and, in so doing, helps to sustain the City’s cultures and norms of financial practice. Specifying the role of postgraduate education in reproducing these
situated City practices is significant because, although geographical variegation in working practices between international financial centres has been widely reported, less attention has been paid to how such institutionally embedded differences are created and sustained. By identifying education as one mechanism of creation and sustenance, our analysis enhances understanding of how the institutional landscapes that underlie financial centres might be maintained or, when necessary, challenged; challenge being significant in relation to attempts to reform practices and cultures in international financial centres in the wake of the 2007–08 crisis
Dynamical aspects of mean field plane rotators and the Kuramoto model
The Kuramoto model has been introduced in order to describe synchronization
phenomena observed in groups of cells, individuals, circuits, etc... We look at
the Kuramoto model with white noise forces: in mathematical terms it is a set
of N oscillators, each driven by an independent Brownian motion with a constant
drift, that is each oscillator has its own frequency, which, in general,
changes from one oscillator to another (these frequencies are usually taken to
be random and they may be viewed as a quenched disorder). The interactions
between oscillators are of long range type (mean field). We review some results
on the Kuramoto model from a statistical mechanics standpoint: we give in
particular necessary and sufficient conditions for reversibility and we point
out a formal analogy, in the N to infinity limit, with local mean field models
with conservative dynamics (an analogy that is exploited to identify in
particular a Lyapunov functional in the reversible set-up). We then focus on
the reversible Kuramoto model with sinusoidal interactions in the N to infinity
limit and analyze the stability of the non-trivial stationary profiles arising
when the interaction parameter K is larger than its critical value K_c. We
provide an analysis of the linear operator describing the time evolution in a
neighborhood of the synchronized profile: we exhibit a Hilbert space in which
this operator has a self-adjoint extension and we establish, as our main
result, a spectral gap inequality for every K>K_c.Comment: 18 pages, 1 figur
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Validation of the Decipher Genomic Classifier in Patients receiving Salvage Radiotherapy without Hormone Therapy after Radical Prostatectomy - An Ancillary Study of the SAKK 09/10 Randomized Clinical Trial.
BACKGROUND
The Decipher genomic classifier (GC) has shown to independently prognosticate outcomes in prostate cancer. The objective of this study was to validate the GC in a randomized phase 3 trial of dose-escalated salvage radiotherapy (SRT) after radical prostatectomy.
PATIENTS AND METHODS
A clinical grade whole-transcriptome assay was performed on RP samples obtained from patients enrolled in SAKK 09/10, a phase 3 trial of 350 men with biochemical recurrence post-radical prostatectomy randomized to 64Gy vs. 70Gy without concurrent hormonal therapy or pelvic nodal radiotherapy (RT). A pre-specified statistical plan was developed to assess the impact of the GC on clinical outcomes. The primary endpoint was biochemical progression; secondary endpoints were clinical progression and time to hormone therapy. Multivariable analyses adjusted for age, T-category, Gleason score, post-radical prostatectomy persistent prostate-specific antigen (PSA), PSA at randomization, and randomization arm were conducted, accounting for competing risks.
RESULTS
The analytic cohort of 226 patients was representative of the overall trial, with median follow-up of 6.3 years (IQR 6.1-7.2). GC (high vs. low-intermediate) was independently associated with biochemical progression (subdistribution hazard ratio [sHR] 2.26 [95% CI 1.42-3.60], p<0.001), clinical progression (HR 2.29 [95% CI 1.32-3.98], p=0.003), and use of hormone therapy (sHR 2.99 [95% CI 1.55-5.76], p=0.001). GC high patients had 5-year freedom from biochemical progression of 45% vs. 71% for GC low-intermediate. Dose escalation did not benefit the overall cohort, nor patients with lower vs. higher GC scores.
CONCLUSIONS
This study represents the first contemporary randomized controlled trial in patients treated with early SRT without concurrent hormone therapy or pelvic nodal RT that has validated the prognostic utility of the GC. Independent of standard clinicopathologic variables and RT dose, high-GC patients were more than twice as likely than lower-GC patients to experience biochemical and clinical progression and receive of salvage hormone therapy. This data confirms the clinical value of Decipher GC to personalize the use of concurrent systemic therapy in the postoperative salvage setting
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