Pertukaran Sosial Pada Masyarakat Petambak: Kajian Struktur Sosial Sebuah Desa Kawasan Pertambakan Di Sulawesi Selatan

An important aspect of society in brackish water agro-ecosystem is the nature of social exchange between each party found in the social system. This is very much related to various social status in that society. An analysis on social exchange pattern will be important to identify which linkages that might lead to a more integrative social structure. With a case study of a brackish-based society in South Sulawesi, the analysis is directed toward a "mapping" of social exchange in the society. Spesifically, the study is related to exchange pattern between Ponggawa and Sawi in terms of patron-client approach, tenure system, and its role in establishing social structure of the society. Some important findings of the study are: (1) most interactions between owner and renter, owner and share holder, owner and sawi, renter and share holder, renter and sawi, and share holder and sawi, are institutionalized through ponggawa-sawi relationship, share holding, and renting; (2) ponggawa-sawi relationship in terms of patron-client linkages dominated by imited exchanges tends to create segmental social structure, while share holding and renting that are dominated by general exchange pattern tend to create a more integrative social structure; (3) imbalance exchanged to both parties; ponggawa is in exploitative side, while sawi is in sub-ordinated one; and (4) strategy for society development in the study site should then consider those social exchange patterns as one most important factors to be considered. This is especially central for the implementation of cooperative and credit program directed toward parties enggaged in those exchange patterns

Multiple self-splicing introns in the 16S rRNA genes of giant sulfur bacteria

The gene encoding the small subunit rRNA serves as a prominent tool for the phylogenetic analysis and classification of Bacteria and Archaea owing to its high degree of conservation and its fundamental function in living organisms. Here we show that the 16S rRNA genes of not-yet-cultivated large sulfur bacteria, among them the largest known bacterium Thiomargarita namibiensis, regularly contain numerous self-splicing introns of variable length. The 16S rRNA genes can thus be enlarged to up to 3.5 kb. Remarkably, introns have never been identified in bacterial 16S rRNA genes before, although they are the most frequently sequenced genes today. This may be caused in part by a bias during the PCR amplification step that discriminates against longer homologs, as we show experimentally. Such length heterogeneity of 16S rRNA genes has so far never been considered when constructing 16S rRNA-based clone libraries, even though an elongation of rRNA genes due to intervening sequences has been reported previously. The detection of elongated 16S rRNA genes has profound implications for common methods in molecular ecology and may cause systematic biases in several techniques. In this study, catalyzed reporter deposition–fluorescence in situ hybridization on both ribosomes and rRNA precursor molecules as well as in vitro splicing experiments were performed and confirmed self-splicing of the introns. Accordingly, the introns do not inhibit the formation of functional ribosomes

Comparative Study of Mechanical Properties of MWCNTS/ Epoxy and SWCNTS/ Epoxy Composites

تم دمج انابيب كاربونية نانوية احادية الطبقة وانابيب كاربونية نانوية متعددة الطبقات مع الايبوكسي وبتراكيز وزنية مختلفة تتراوح بحدود (0.1, 0.3, 0.5, 1 wt. %) وقد تم تصنيع هذه المادة النانوية بطريقة السباكة. من اهم التطبيقات لهذه المادة النانوية المركبة هي في المتحسسات, المشغلات والرادار  ولهذه الدراسة اجريت العديد من الاختبارات الميكانيكية مثل: اختبار الشد ، اختبار الانحناء والصلادة. كذلك تم استخدام العديد من الفحوصات لتحسين البنية المجهرية مثل الفحص بالمجهر الالكتروني الماسح ،  الفحص بحيود الاشعة السينية والفحص بمطياف رامان. وقد اظهرت نتائج هذا العمل ان هناك تحسن واضح في الخواص الميكانيكية للمادة النانوية المركبة مثل معامل يونك ، مقاومة الشد القصوى ، مقاومة الانحناء وصلادة شور. وقد اظهرت الصور المجهرية المؤخوذة بالمجهر الالكتروني الماسح ان الانابيب الكاربونية احادية الطبقة والمتعددة الطبقات قد تم تشتيتها بشكل متجانس في الاليبوكسي. من ناحية اخرى اظهرت نتائج الفحص بمطياف رامان وحيود الاشعة السينية نفس النتائج المجهر الالكتروني الماسح. اخيرا قد اظهرت جميع نتائج الخواص الميكانيكية والبنية المجهرية بأن الانابيب الكاربونية احادية الطبقة تعطي نتائج افضل من نظيرتها ذات الانابيب الكاربونية المتعددة الطبقات. The single – walled carbon nanotubes (SWCNTs) and multi – walled carbon nanotubes (MWCNTs) embedded into resin matrix with different weight concentrations ranging about (0.1, 0.3, 0.5 and 1 wt. %), the nanocomposites are synthesized by casting method. The main applications of this nanocomposites are in the sensors, actuators, radar. Mechanical tests were done for this study such as: tensile test, bending test and hardness test. Also many examinations were utilized to define the microstructure like scanning electron microscopy (SEM), X-ray diffraction and Raman spectroscopy. The results of this work showed that obviously an improvement in mechanical properties of the processed nanocomposites such as young’s modulus, ultimate tensile strength, bending strength and Shore hardness. Also the micrographs of SEM demonstrated that SWCNTs and MWCNTs homogeneously dispersed into epoxy. On the other hand Raman spectra and XRD revealed that same results for SEM. Finally all the results for mechanical properties and microstructure evaluation show that SWCNTs give extremely higher values and properties than MWCNTs

Stem Cell Transplantation As A Dynamical System: Are Clinical Outcomes Deterministic?

Outcomes in stem cell transplantation (SCT) are modeled using probability theory. However the clinical course following SCT appears to demonstrate many characteristics of dynamical systems, especially when outcomes are considered in the context of immune reconstitution. Dynamical systems tend to evolve over time according to mathematically determined rules. Characteristically, the future states of the system are predicated on the states preceding them, and there is sensitivity to initial conditions. In SCT, the interaction between donor T cells and the recipient may be considered as such a system in which, graft source, conditioning and early immunosuppression profoundly influence immune reconstitution over time. This eventually determines clinical outcomes, either the emergence of tolerance or the development of graft versus host disease. In this paper parallels between SCT and dynamical systems are explored and a conceptual framework for developing mathematical models to understand disparate transplant outcomes is proposed.Comment: 23 pages, 4 figures. Updated version with additional data, 2 new figures and editorial revisions. New authors adde

Spin Dynamics of the LAGEOS Satellite in Support of a Measurement of the Earth's Gravitomagnetism

LAGEOS is an accurately-tracked, dense spherical satellite covered with 426 retroreflectors. The tracking accuracy is such as to yield a medium term (years to decades) inertial reference frame determined via relatively inexpensive observations. This frame is used as an adjunct to the more difficult and data intensive VLBI absolute frame measurements. There is a substantial secular precession of the satellite's line of nodes consistent with the classical, Newtonian precession due to the non-sphericity of the earth. Ciufolini has suggested the launch of an identical satellite (LAGEOS-3) into an orbit supplementary to that of LAGEOS-1: LAGEOS-3 would then experience an equal and opposite classical precession to that of LAGEOS-1. Besides providing a more accurate real-time measurement of the earth's length of day and polar wobble, this paired-satellite experiment would provide the first direct measurement of the general relativistic frame-dragging effect. Of the five dominant error sources in this experiment, the largest one involves surface forces on the satellite, and their consequent impact on the orbital nodal precession. The surface forces are a function of the spin dynamics of the satellite. Consequently, we undertake here a theoretical effort to model the spin ndynamics of LAGEOS. In this paper we present our preliminary results.Comment: 16 pages, RevTeX, LA-UR-94-1289. (Part I of II, postscript figures in Part II

Correlation studies of open and closed states fluctuations in an ion channel: Analysis of ion current through a large conductance locust potassium channel

Ion current fluctuations occurring within open and closed states of large conductance locust potassium channel (BK channel) were investigated for the existence of correlation. Both time series, extracted from the ion current signal, were studied by the autocorrelation function (AFA) and the detrended fluctuation analysis (DFA) methods. The persistent character of the short- and middle-range correlations of time series is shown by the slow decay of the autocorrelation function. The DFA exponent $\alpha$ is significantly larger than 0.5. The existence of strongly-persistent long-range correlations was detected only for closed-states fluctuations, with $\alpha=0.98\pm0.02$. The long-range correlation of the BK channel action is therefore determined by the character of closed states. The main outcome of this study is that the memory effect is present not only between successive conducting states of the channel but also independently within the open and closed states themselves. As the ion current fluctuations give information about the dynamics of the channel protein, our results point to the correlated character of the protein movement regardless whether the channel is in its open or closed state.Comment: 12 pages, 5 figures; to be published in Phys. Rev.

Numerical Investigation of Heat Transfer and Friction Factor Characteristics in a Circular Tube Fitted with V-Cut Twisted Tape Inserts

Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio (y=2.93) and different cut depths (w=0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Classical twisted tape (CTT) with different twist ratios (y=2.93, 3.91, 4.89) were also studied for comparison. The results show that the enhancement of heat transfer rate induced by the classical and V-cut twisted tape inserts increases with the Reynolds number and decreases with twist ratio. The results also revealed that the V-cut twisted tape with twist ratio y=2.93 and cut depth w=0.5 cm offered higher heat transfer rate with significant increases in friction factor than other tapes. In addition the results of V-cut twist tape compared with experimental and simulated data of right-left helical tape inserts (RLT), it is found that the V-cut twist tape offered better thermal contact between the surface and the fluid which ultimately leads to a high heat transfer coefficient. Consequently, 107% of maximum heat transfer was obtained by using this configuration