31,801 research outputs found
Chan An Ancient Maya Farming Community
No full textThe farming community of Chan thrived for over twenty centuries, surpassing the longevity of many larger Maya urban centers. Between 800 BC and 1200 AD it was a major food production center, and this collection of essays reveals the important role played by Maya farmers in the development of ancient Maya society. Chan offers a synthesis of compelling and groundbreaking discoveries gathered over ten years of research at this one archaeological site in Belize. The contributors develop three central themes, which structure the book. They examine how sustainable farming practices maintained the surrounding forest, allowing the community to exist for two millennia. They trace the origins of elite Maya state religion to the complex religious belief system developed in small communities such as Chan. Finally, they describe how the group-focused political strategies employed by local leaders differed from the highly hierarchical strategies of the Classic Maya kings in their large cities. In breadth, methodology, and findings, this volume scales new heights in the study of Maya society and culture.Cover -- Title -- Copyright -- Contents -- List of Figures -- List of Tables -- Foreword -- Acknowledgments -- 1. Introducing the Chan Site: Farmers in Complex Societies -- Part 1. Time, Space, and Landscapes -- 2. A Changing Cultural Landscape: Settlement Survey and GIS at Chan -- 3. Ceramics and Chronology at Chan -- 4. Agricultural Practices at Chan: Farming and Political Economy in an Ancient Maya Community -- 5. Agroforestry and Agricultural Production of the Ancient Maya at Chan -- Part 2. Life in a Farming Community Center -- 6. Ritual in a Farming Community -- 7. Nonroyal Governance at Chan's Community Center -- 8. "Empty" Spaces and Public Places: A Microscopic View of Chan's Late Classic West Plaza -- Part 3. Diversity across the Chan Community -- 9. Recognizing Difference in Small-Scale Settings: An Examination of Social Identity Formation at the Northeast Group, Chan -- 10. Organization of Chert Tool Economy during the Late and Terminal Classic Periods at Chan: Preliminary Thoughts Based upon Debitage Analyses -- 11. Limestone Quarrying and Household Organization at Chan -- Part 4. Bodies, Material Culture, and Meaning -- 12. The Chan Community: A Bioarchaeological Perspective -- 13. Creating Community with Shell -- 14. Obsidian Acquisition, Trade, and Regional Interaction at Chan -- 15. Contextualizing Ritual Behavior: Caches, Burials, and Problematical Deposits from Chan's Community Center -- Part 5. Conclusion -- 16. Learning from an Ancient Maya Farming Community -- References -- List of Contributors -- Index -- A -- B -- C -- D -- E -- F -- G -- H -- I -- J -- K -- L -- M -- N -- O -- P -- Q -- R -- S -- T -- V -- W -- X -- YThe farming community of Chan thrived for over twenty centuries, surpassing the longevity of many larger Maya urban centers. Between 800 BC and 1200 AD it was a major food production center, and this collection of essays reveals the important role played by Maya farmers in the development of ancient Maya society. Chan offers a synthesis of compelling and groundbreaking discoveries gathered over ten years of research at this one archaeological site in Belize. The contributors develop three central themes, which structure the book. They examine how sustainable farming practices maintained the surrounding forest, allowing the community to exist for two millennia. They trace the origins of elite Maya state religion to the complex religious belief system developed in small communities such as Chan. Finally, they describe how the group-focused political strategies employed by local leaders differed from the highly hierarchical strategies of the Classic Maya kings in their large cities. In breadth, methodology, and findings, this volume scales new heights in the study of Maya society and culture.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
Chan-Sik Kim
No full text학위논문(박사)--아주대학교 일반대학원 :의학과,2014. 2I. INTRODUCTION 1
A. Age-related oxidative renal injury 1
B. AGEs and oxidative stress 2
C. High mobility group box protein-1 and receptor for AGE 3
D. Role of podocyte in glomerular pathobiology 3
E. Exercise and renal injury 4
F. Korean red ginseng and renal injury 5
G. Obesity-related renal injury 6
H. Aims of study 6
II. MATERIALS AND METHODS 8
A. KRG preparation 8
B. Animals and experimental design 8
C. Analysis of metabolic data 9
D. In vitro assay of the cross-linking of glycated proteins 10
E. Immunohistochemical staining 10
F. Double staining for TUNEL and Wilms tumor antigen-1 11
G. Apoptosis analysis 11
H. Statistical analysis 12
III. Results 13
A. Body weight and blood lipid profile 13
B. CML accumulation in renal tissues 16
C. Oxidative DNA damage in renal tissues 18
D. Apoptosis assay in renal tissues 20
E. Expression of Bax and Bcl-2 in renal tissues 22
F. Caspase-3 activation 25
G. Glomerular podocyte loss 27
H. Inhibitory effect of KRG on glycated proteins cross-linking in vitro. 31
I. Body weight and blood lipid profile 33
J. Oxidative DNA damage in renal tissues 36
K. Protein glycations in renal tissues 38
L. Apoptosis assay in renal tissues 40
M. HMGB1 cytoplasmic translocalization in renal tissues 42
N. RAGE Expression in renal tissues 44
IV. DISCUSSION 47
V. CONCLUSION 53
VI. REFERENCES 54
국문요약 67MasterA decline in renal function is seen commonly in aging. Aging further increase oxidative stress in the kidney and are associated with reduced renal function. Aging is progressive accumulation of oxidative agents. Advanced glycation end products (AGEs) and advanced lipoxidation end products (ALEs) formation has been implicated in the aging process. Obesity induced by a high-fat diet (HFD) may reduce renal function. However, the impact of obese on the age-related renal disease is not well understood. Exercise reduces oxidative stress. Korean red ginseng (KRG) has been reported to ameliorate oxidative tissue injury and has an anti-aging effect. The purpose of this study was to investigate whether HFD would accelerate ᴅ-galactose (GAL)-induced renal injury and to examine the preventive effects of a regular exercise and KRG on GAL/HFD -induced renal injury.
In the first experiment, age-related renal injury was induced by an administration with GAL (100 mg/kg, i.p.) in the absence or presence of high-fat diet (60% kcal as fat) for 9 weeks. The exercise group was trained on a motorized treadmill for 60 min/day, 5 times/week over the same period. In the second experiment, in vitro inhibitory effect of KRG on AGEs-cross-linking was examined by enzyme-linked immunosorbent assay (ELISA), and KRG (200 mg/kg/day) was given to GAL plus HFD-induced aging rats for 9 weeks.
Immunohistochemical staining for 8-OHdG (a specific marker of oxidative DNA damage) and CMLs (a marker of both glycation and lipoxidation reactions) revealed that GAL-treated rats fed a HFD showed aggravated renal injury associated with more pronounced renal AGEs/ALEs formation and oxidative DNA damage. In TUNEL assay, the numbers of TUNEL-positive cell in the GAL/HFD group were significantly higher than the GAL group. The expression of activated caspase-3 protein and Bax/Bcl-2 ratio also were significantly increased in the GAL/HFD group than that in the GAL group. Moreover, imuunohistochemical staining for synaptopodin and WT-1, well-known podocyte markers, revealed that HFD aggravates the loss of podocytes in renal glomeruli. However, the regular exercise restored all these renal changes in HFD plus GAL-treated rats.
KRG inhibited AGEs and collagen cross-link at ten-fold less concentration (IC50=55.65 μg/ml) than aminoguanidine (IC50=563.54 μg/ml), a well-known glycation inhibitor. When rats were fed with a HFD for 9 weeks in GAL-induced aging rats, renal AGEs accumulation, extracellular high mobility group box 1 protein (HMGB1), a signal of tissue damage) and receptor for AGE (RAGE) were extensively expressed in renal tissues of the GAL/HFD group than that in the GAL group. HMGB1 was clearly translocated from the nucleus to the cytoplasm in renal tubular epithelial cells. However, treatment of HFD plus GAL-induced aging rats with KRG restored all these renal changes.
In summary, when rats were fed with a HFD for 9 weeks in GAL-induced aging rats, oxidative DNA damage, protein glycations, renal cell apoptosis and cytoplasmic translocation of HMGB1 were caused in renal glomerular cells and tubular epithelial cells. However, the regular exercise and KRG treatment restored all these renal changes in GAL/HFD-treated rats. Therefore, this study suggested that long-term HFD may accelerate the deposition of AGEs/ALEs and oxidative renal injury in GAL-treated rats. This HFD-increased renal injury in GAL-induced aging rats could be suppressed by regular exercise and KRG through the repression of oxidative injury
Cnemaspis selamatkanmerapoh Grismer, Wood, Mohamed, Chan, Heinz, Sumarli, Chan & Loredo 2013
No full text<i>Cnemaspis selamatkanmerapoh</i> Grismer, Wood, Mohamed, Chan, Heinz, Sumarli, Chan & Loredo, 2013 <p> <b>Holotype and type locality:</b> Adult male (LSUHC 11016) from “ Gua Gunting, Merapoh, Pahang, Peninsular</p> <p> Malaysia (4°42.069 N 101°58.512 E; at 257 m elevation).” <b>Distribution:</b> Known only from the type locality.</p>Published as part of <i>Grismer, L. Lee & Quah, Evan S. H., 2019, An updated and annotated checklist of the lizards of Peninsular Malaysia, Singapore, and their adjacent archipelagos, pp. 230-248 in Zootaxa 4545 (2)</i> on page 237, DOI: 10.11646/zootaxa.4545.2.4, <a href="http://zenodo.org/record/2618805">http://zenodo.org/record/2618805</a>
Nenasa Chan & Yang 1994
No full textKey to species of Nenasa 1 Male forewing with an oblique pale yellow stripe from its base to the middle (CHAN & YANG 1994: fig. 4D). Rostrum with third segment longer than wide. Hind margins of male pygofer concave (CHAN & YANG 1994: Fig. 4E). Phallobase narrow (CHAN & YANG 1994: Figs 4G, H). Male anal tube, in dorsal view, elongate, narrowing apically, without apical concavity (CHAN & YANG 1994: fig. 4F). Taiwan......................................... N. obliqua Chan & Yang, 1994 – Male forewing with a large light yellow spot basally and a light yellow inner margin (Figs 1, 2). Rostrum with third segment as long as wide (Fig. 11). Hind margins of male pygofer straight in lower two thirds, convex in upper third (Fig. 18). Phallobase wide (Figs 15–17). Male anal tube, in dorsal view, wide, almost rounded, with weak apical concavity (Fig. 22). Fujian............................................ N. ouchii sp. nov.Published as part of Gnezdilov, Vladimir M., 2018, A new species of the genus Nenasa (Hemiptera: Fulgoroidea: Caliscelidae) from mainland China, pp. 539-544 in Acta Entomologica Musei Nationalis Pragae 58 (2) on page 543, DOI: 10.2478/aemnp-2018-0043, http://zenodo.org/record/448891
Differentially Oblivious Database Joins: Overcoming the Worst-Case Curse of Fully Oblivious Algorithms
Get PDFNumerous high-profile works have shown that access patterns to even encrypted databases can leak secret information and sometimes even lead to reconstruction of the entire database. To thwart access pattern leakage, the literature has focused on oblivious algorithms, where obliviousness requires that the access patterns leak nothing about the input data.
In this paper, we consider the Join operator, an important database primitive that has been extensively studied and optimized. Unfortunately, any fully oblivious Join algorithm would require always padding the result to the worst-case length which is quadratic in the data size N. In comparison, an insecure baseline incurs only O(R + N) cost where R is the true result length, and in the common case in practice, R is relatively short. As a typical example, when R = O(N), any fully oblivious algorithm must inherently incur a prohibitive, N-fold slowdown relative to the insecure baseline. Indeed, the (non-private) database and algorithms literature invariably focuses on studying the instance-specific rather than worst-case performance of database algorithms. Unfortunately, the stringent notion of full obliviousness precludes the design of efficient algorithms with non-trivial instance-specific performance.
To overcome this worst-case performance barrier of full obliviousness and enable algorithms with good instance-specific performance, we consider a relaxed notion of access pattern privacy called (ε, δ)-differential obliviousness (DO), originally proposed in the seminal work of Chan et al. (SODA'19). Rather than insisting that the access patterns leak no information whatsoever, the relaxed DO notion requires that the access patterns satisfy (ε, δ)-differential privacy. We show that by adopting the relaxed DO notion, we can obtain efficient database Join mechanisms whose instance-specific performance approximately matches the insecure baseline, while still offering a meaningful notion of privacy to individual users. Complementing our upper bound results, we also prove new lower bounds regarding the performance of any DO Join algorithm.
Differential obliviousness (DO) is a new notion and is a relatively unexplored territory. Following the pioneering investigations by Chan et al. and others, our work is among the very first to formally explore how DO can help overcome the worst-case performance curse of full obliviousness; moreover, we motivate our work with database applications. Our work shows new evidence why DO might be a promising notion, and opens up several exciting future directions
Cyrtodactylus guakanthanensis Grismer, Belabut, Quah, Chan, Wood & Hasim 2014
No full textCyrtodactylus guakanthanensis Grismer, Belabut, Quah, Chan, Wood & Hasim, 2014 Holotype and type locality: Adult male (LSUHC 11322) from “Gua Kanthan, Perak, Peninsular Malaysia (4°45.685’N, 101°07.322’E; 45 m).” Distribution: Known only from the type locality.Published as part of Grismer, L. Lee & Quah, Evan S. H., 2019, An updated and annotated checklist of the lizards of Peninsular Malaysia, Singapore, and their adjacent archipelagos, pp. 230-248 in Zootaxa 4545 (2) on page 238, DOI: 10.11646/zootaxa.4545.2.4, http://zenodo.org/record/261880
Algorithms and complexity for periodic real-time scheduling
Get PDFWe investigate the preemptive scheduling of periodic tasks with hard deadlines. We show that, even in the uniprocessor case, no pseudopolynomial-time algorithm can test the feasibility of a task system within a constant speedup bound, unless P = NP. This result contrasts with recent results for sporadic task systems. For two special cases, synchronous task systems and systems with a constant number of different task types, we provide the first polynomial-time constant-speedup feasibility tests for multiprocessor platforms. Furthermore, we show that the problem of testing feasibility is coNP-hard for synchronous multiprocessor task systems. The complexity of some of these problems has been open for a long time. We also propose a weight maximization variant of the feasibility problem, where every task has a nonnegative weight, and the goal is to find a subset of tasks that can be scheduled feasibly and has maximum weight. We give the first constant-speed, constant-approximation algorithm for the case of synchronous task systems, together with related hardness results. © 2012 ACM
Magmatism associated with Gondwanaland rifting and Neo-Tethyan oceanic basin development: evidence from the Mamonia Complex, SW Cyprus
No full textSome remarks on first passage of Lévy processes, the American put and pasting principles
Get PDFThe purpose of this article is to provide, with the help of a fluctuation identity, a generic link between a number of known identities for the first passage time and overshoot above/below a fixed level of a Lévy process and the solution of Gerber and Shiu [Astin Bull. 24 (1994) 195–220], Boyarchenko and Levendorskii [Working paper series EERS 98/02 (1998), Unpublished manuscript (1999), SIAM J. Control Optim. 40 (2002) 1663–1696], Chan [Original unpublished manuscript (2000)], Avram, Chan and Usabel [Stochastic Process. Appl. 100 (2002) 75–107], Mordecki [Finance Stoch. 6 (2002) 473–493], Asmussen, Avram and Pistorius [Stochastic Process. Appl. 109 (2004) 79–111] and Chesney and Jeanblanc [Appl. Math. Fin. 11 (2004) 207–225] to the American perpetual put optimal stopping problem. Furthermore, we make folklore precise and give necessary and sufficient conditions for smooth pasting to occur in the considered problem
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