Is the Progress Zone Model a Victim of Progress?

نویسندگان

چکیده

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Is the Progress Zone Model a Victim of Progress?

The prevailing view has long been that mesenchymal cells at the apex of the vertebrate limb bud proliferate in a progress zone (PZ) under the influence of the apical ectodermal ridge (AER). According to the PZ model, proximodistal cell fates are specified according to the time spent in the PZ. New results, considered along with some earlier findings, fail to support this model.

متن کامل

investigating the feasibility of a proposed model for geometric design of deployable arch structures

deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...

Hard-X-ray Zone Plates: Recent Progress

The technology to focus hard-X-rays (photon energy larger than 1–2 keV) has made great progress in the past three years. The progress was particularly spectacular for lenses based on the Fresnel zone plate concept. The spatial resolution notably increased by a factor of three, opening up entirely new domains of application, specifically in biomedical research. As we shall see, this evolution is...

متن کامل

epistemological foundations and the iranian islamic model of progress.

every kind of theorization and progress modeling, wether contiousely or uncontiousely, is based on and benefited from the epistemological, cosmological, anthropological, axiological foundations. for the iranian islamic model of progress, however, it is compulsary to recognize and refer to its own speculative understructures and use them intentionaly and exactly to produce the  best possible mod...

متن کامل

Providing a Desirable Model of Competition for Educational Progress in University (Case study: Islamic Azad University)

Introduction: Many phenomena have changed and changes is no longer an opportunity for higher education and universities, but it is a necessity. Therefore, the aim of this study was to improve the future competitiveness of Islamic Azad University units. Methods: The research was developmental and applied with a mixed approach. The statistical population and sample in the qualitative section incl...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Cell

سال: 2002

ISSN: 0092-8674

DOI: 10.1016/s0092-8674(02)01011-5