From microscopic to macroscopic descriptions of cell\ud migration on growing domains

Cell migration and growth are essential components of the development of multicellular organisms. The role of various cues in directing cell migration is widespread, in particular, the role of signals in the environment in the control of cell motility and directional guidance. In many cases, especially in developmental biology, growth of the domain also plays a large role in the distribution of cells and, in some cases, cell or signal distribution may actually drive domain growth. There is a ubiquitous use of partial differential equations (PDEs) for modelling the time evolution of cellular density and environmental cues. In the last twenty years, a lot of attention has been devoted to connecting macroscopic PDEs with more detailed microscopic models of cellular motility, including models of directional sensing and signal transduction pathways. However, domain growth is largely omitted in the literature. In this paper, individual-based models describing cell movement and domain growth are studied, and correspondence with a macroscopic-level PDE describing the evolution of cell density is demonstrated. The individual-based models are formulated in terms of random walkers on a lattice. Domain growth provides an extra mathematical challenge by making the lattice size variable over time. A reaction-diffusion master equation formalism is generalised to the case of growing lattices and used in the derivation of the macroscopic PDEs

Evaluasi Program Corporate Social Responsibility “Organic Integrated System” PT. Pembangkitan Jawa-Bali Unit Pembangkitan Paiton

Penelitian ini dilakukan untuk mengevaluasi program Corporate Social Responsibility “Organic Integrated System” yang dijalankan oleh divisi umum dan CSR PT. Pembangkitan Jawa – Bali Unit Pembangkitan Paiton. Di dalam melaksanakan program Corporate Social Responsibility “Organic Integrated System” ini, PT. Pembangkitan Jawa – Bali Unit Pembangkitan Paiton bekerja sama dengan Lembaga Swadaya Masyarakat Sekola Konang dan Kelompok Suko Tani sebagai publik sasarannya. Penelitian ini menggunakan pendekatan kualitatif, dengan metode studi kasus intrinsik.Dalam penelitian evaluasi program Corporate Social Responsibility “Organic Integrated System”, peneliti menemukan bahwa tujuan dari program ini adalah peningkatan kapasitas produktivitas dan Sumber Daya Manusia. Peneliti juga menemukan adanya program partisipatif dalam perencanaan program ini serta adanya hambatan dari kepala desa dalam pelaksanaan program

Distinct mechanisms underlie pattern formation in the skin and skin appendages

Patterns form with the break of homogeneity and lead to the emergence of new structure or arrangement. There are different physiological and pathological mechanisms that lead to the formation of patterns. Here, we first introduce the basics of pattern formation and their possible biological basis. We then discuss different categories of skin patterns and their potential underlying molecular mechanisms. Some patterns, such as the lines of Blaschko and Naevus, are based on cell lineage and genetic mosaicism. Other patterns, such as regionally specific skin appendages, can be set by distinct combinatorial molecular codes, which in turn may be set by morphogenetic gradients. There are also some patterns, such as the arrangement of hair follicles (hair whorls) and fingerprints, which involve genetics as well as stochastic epigenetic events based on physiochemical principles. Many appendage primordia are laid out in developmental waves. In the adult, some patterns, such as those involving cycling hair follicles, may appear as traveling waves in mice. Since skin appendages can renew themselves in regeneration, their size and shape can still change in the adult via regulation by hormones and the environment. Some lesion patterns are based on pathological changes involving the above processes and can be used as diagnostic criteria in medicine. Understanding the different mechanisms that lead to patterns in the skin will help us appreciate their full significance in morphogenesis and medical research. Much remains to be learned about complex pattern formation, if we are to bridge the gap between molecular biology and organism phenotypes. Birth Defects Research (Part C) 78:280-291, 2006. © 2006 Wiley-Liss, Inc

Increasing the effective participation of women in food and nutrition security in Africa

What can be done to increase the effective participation of women in food and nutrition security in Africa? This brief advocates a two-pronged approach. First, eradicate discrimination against women, and second, promote catch-up by implementing more active measures in key areas such as control over land, water, and other assets, and investment in education, health, child care, and other services for women. Since the set of actions that are most appropriate in a given situation will be context specific, we present examples of approaches that have worked in Sub-Saharan Africa." from TextNutrition ,Property rights ,Child care ,Education ,Women ,Gender ,

Contesting the cruel treatment of abortion-seeking women

NOTICE: this is the author’s version of a work that was accepted for publication in Reproductive Health Matters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in REPRODUCTIVE HEALTH MATTERS, [VOL 22, ISSUE 44, (2014)] DOI: 10.1016/S0968-8080(14)44818-

Gravitational wave generation from bubble collisions in first-order phase transitions: an analytic approach

Gravitational wave production from bubble collisions was calculated in the early nineties using numerical simulations. In this paper, we present an alternative analytic estimate, relying on a different treatment of stochasticity. In our approach, we provide a model for the bubble velocity power spectrum, suitable for both detonations and deflagrations. From this, we derive the anisotropic stress and analytically solve the gravitational wave equation. We provide analytical formulae for the peak frequency and the shape of the spectrum which we compare with numerical estimates. In contrast to the previous analysis, we do not work in the envelope approximation. This paper focuses on a particular source of gravitational waves from phase transitions. In a companion article, we will add together the different sources of gravitational wave signals from phase transitions: bubble collisions, turbulence and magnetic fields and discuss the prospects for probing the electroweak phase transition at LISA.Comment: 48 pages, 14 figures. v2 (PRD version): calculation refined; plots redone starting from Fig. 4. Factor 2 in GW energy spectrum corrected. Main conclusions unchanged. v3: Note added at the end of paper to comment on the new results of 0901.166

Time-reversible Born-Oppenheimer molecular dynamics

We present a time-reversible Born-Oppenheimer molecular dynamics scheme, based on self-consistent Hartree-Fock or density functional theory, where both the nuclear and the electronic degrees of freedom are propagated in time. We show how a time-reversible adiabatic propagation of the electronic degrees of freedom is possible despite the non-linearity and incompleteness of the self-consistent field procedure. Time-reversal symmetry excludes a systematic long-term energy drift for a microcanonical ensemble and the number of self-consistency cycles can be kept low (often only 2-4 cycles per nuclear time step) thanks to a good initial guess given by the adiabatic propagation of the electronic degrees of freedom. The time-reversible Born-Oppenheimer molecular dynamics scheme therefore combines a low computational cost with a physically correct time-reversible representation of the dynamics, which preserves a detailed balance between propagation forwards and backwards in time.Comment: 4 pages, 4 figure

A Multi-Moded RF Delay Line Distribution System for the Next Linear Collider

The Delay Line Distribution System (DLDS) is an alternative to conventional pulse compression, which enhances the peak power of rf sources while matching the long pulse of those sources to the shorter filling time of accelerator structures. We present an implementation of this scheme that combines pairs of parallel delay lines of the system into single lines. The power of several sources is combined into a single waveguide delay line using a multi-mode launcher. The output mode of the launcher is determined by the phase coding of the input signals. The combined power is extracted from the delay line using mode-selective extractors, each of which extracts a single mode. Hence, the phase coding of the sources controls the output port of the combined power. The power is then fed to the local accelerator structures. We present a detailed design of such a system, including several implementation methods for the launchers, extractors, and ancillary high power rf components. The system is designed so that it can handle the 600 MW peak power required by the NLC design while maintaining high efficiency.Comment: 25 pages, 11 figure

Analisa Pendapatan dan Persepsi Petani Keramba terhadap Keberadaan Pt.aquafarm Nusantara (Studi Kasus : Petani Keramba Dikecamatan Girsang Sipanganbolon Kabupaten Simalungun)

The purposes of this research is to analyze the income and perception of cage farmersagainst existence PT.Aquafarmnusantara on subdistrictGirsangsipanganbolon regencySimalungun .The data used in this study were primer and obtained from 60 cage farmers bysimple random sampling. The analysis method used in this study is Quantitative DescriptiveAnalysis and Path analysis. The test of validity and reliability of the instrument based on value by 0,3%. The result shows that level of education, spacious cages, experience, feed of fish and fingerlings significant to total fish production and level of education, spaciouscages, experience, feed of fish, fingerlings and total fish production significant to level of income of cage farmers and the result of validity and reliability test shows that the questions of perception are valid and reliable