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2014

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Articles 12271 - 12299 of 12299

Full-Text Articles in Physical Sciences and Mathematics

Global Meteorological Drought – Part 2: Seasonal Forecasts, Will Pozzi Dec 2013

Global Meteorological Drought – Part 2: Seasonal Forecasts, Will Pozzi

Will Pozzi

Global seasonal forecasts of meteorological drought using the standardized precipitation index (SPI) are produced using two data sets as initial conditions: the Global Precipitation Climatology Centre (GPCC) and the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis (ERAI); and two seasonal forecasts of precipitation, the most recent ECMWF seasonal forecast system and climatologically based ensemble forecasts. The forecast evaluation focuses on the periods where precipitation deficits are likely to have higher drought impacts, and the results were summarized over different regions in the world. The verification of the forecasts with lead time indicated that generally for all regions the …

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Name The Experiment! Interpreting Thermodynamic Derivatives As Thought Experiments, David Roundy, Mary Bridget Kustusch, Corrine Manogue Dec 2013

Name The Experiment! Interpreting Thermodynamic Derivatives As Thought Experiments, David Roundy, Mary Bridget Kustusch, Corrine Manogue

Mary Bridget Kustusch

We introduce a series of activities to help students understand the partial derivatives that arise in thermodynamics. Students construct thought experiments that would allow them to measure given partial derivatives. These activities are constructed with a number of learning goals in mind, beginning with helping students to learn to think of thermodynamic quantities in terms of how one can measure or change them. A second learning goal is for students to understand the importance of the quantities held fixed in either a partial derivative or an experiment. Students additionally are given an experimental perspective—particularly when this activity is combined with real laboratory experiments—on the meaning of either fixing …

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Partial Derivative Games In Thermodynamics: A Cognitive Task Analysis, Mary Bridget Kustusch, David Roundy, Corrine Manogue, Tevian Dray Dec 2013

Partial Derivative Games In Thermodynamics: A Cognitive Task Analysis, Mary Bridget Kustusch, David Roundy, Corrine Manogue, Tevian Dray

Mary Bridget Kustusch

Several studies in recent years have demonstrated that upper-division students struggle with the
mathematics of thermodynamics. This paper presents a task analysis based on several expert attempts
to solve a challenging mathematics problem in thermodynamics. The purpose of this paper is twofold.
First, we highlight the importance of cognitive task analysis for understanding expert performance and
show how the epistemic games framework can be used as a tool for this type of analysis, with
thermodynamics as an example. Second, through this analysis, we identify several issues related to
thermodynamics that are relevant to future research into student understanding and learning …

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Formulation And Derivation Of Simultaneous Band Scores Or Simbas, Mark J. Meyer, Jeffrey S. Morris Dec 2013

Formulation And Derivation Of Simultaneous Band Scores Or Simbas, Mark J. Meyer, Jeffrey S. Morris

Mark J Meyer

The formulation and derivation of the Simultaneous Band Score or SimBaS procedure that is implemented and discussed in Bayesian Function-on-Function Regression for Multi-Level Functional Data.

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Transverse And Longitudinal Mass Moving In The Inertial Frame Of Reference, Vildyan Yanbikov Dec 2013

Transverse And Longitudinal Mass Moving In The Inertial Frame Of Reference, Vildyan Yanbikov

Vildyan Yanbikov

Based on the speed of the spread of vector interaction in a moving inertial frame of reference. A calculation of the transversal and longitudinal mass of elementary particles.

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Communicating Climate Change: Are Stories Better Than ‘Just The Facts?’, Michael D. Jones Dr. Dec 2013

Communicating Climate Change: Are Stories Better Than ‘Just The Facts?’, Michael D. Jones Dr.

Michael D. Jones

Postpositive policy scholarship has long asserted the importance of narratives—or stories—in shaping public policy through public opinion. In part, the Narrative Policy Framework (NPF) was developed to empirically test this assertion. To assess the relationship between policy narratives and public opinion, NPF posits several causal mechanisms including narrative transportation. Narrative transportation is a measure used to assess the extent to which individuals exposed to a story are “transported” into that story. NPF hypothesizes that as narrative transportation increases the reader of the story will (i) have more positive affect for characters within the story; and (ii) will find the story …

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Hyperbolic Expressions Of Polynomial Sequences And Parametric Number Sequences Defined By Linear Recurrence Relations Of Order 2, Tian-Xiao He, Peter J.-S. Shiue, Tsui-Wei Weng Dec 2013

Hyperbolic Expressions Of Polynomial Sequences And Parametric Number Sequences Defined By Linear Recurrence Relations Of Order 2, Tian-Xiao He, Peter J.-S. Shiue, Tsui-Wei Weng

Tian-Xiao He

A sequence of polynomial {an(x)} is called a function sequence of order 2 if it satisfies the linear recurrence relation of order 2: an(x) = p(x)an-1(x) + q(x)an-2(x) with initial conditions a0(x) and a1(x). In this paper we derive a parametric form of an(x) in terms of eθ with q(x) = B constant, inspired by Askey's and Ismail's works shown in [2] [6], and [18], respectively. With this method, we give the hyperbolic expressions of Chebyshev polynomials and Gegenbauer-Humbert Polynomials. The applications of the method to construct corresponding hyperbolic form of several well-known identities are also discussed in this paper.

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Graphical Assessment Of Internal And External Calibration Of Logistic Regression Models Using Loess Smoothers, Peter C. Austin Dec 2013

Graphical Assessment Of Internal And External Calibration Of Logistic Regression Models Using Loess Smoothers, Peter C. Austin

Peter Austin

Predicting the probability of the occurrence of a binary outcome or condition is important in biomedical research. While assessing discrimination is an essential issue in developing and validating binary prediction models, less attention has been paid to methods for assessing model calibration. Calibration refers to the degree of agreement between observed and predicted probabilities, and is often assessed by testing lack-of-fit. The objective of our study was to examine the ability of graphical methods to assess calibration of logistic regression models. We examined lack of internal calibration, which was related to mis-specification of the logistic regression model, and lack of …

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Syllabus_Lecture_Notes_Collective_Phenomena_In_Laser_Plasmas_Ii_Phy998_Spring_2014, Serge Y. Kalmykov Dec 2013

Syllabus_Lecture_Notes_Collective_Phenomena_In_Laser_Plasmas_Ii_Phy998_Spring_2014, Serge Y. Kalmykov

Serge Youri Kalmykov

High-power laser radiation beams interacting with a rarefied, fully ionized plasmas are essentially unstable. This fact is mainly due to the excitation of various modes of plasma oscillations, most important of which are electron Langmuir waves and ion acoustic waves. The stimulated scattering processes destroy and deplete the pulse in the as it propagates. On the other hand, at the moderate level of instability, spectral properties of the scattered light may serve as optical diagnostics of the pulse propagation dynamics. Knowing the dynamics of the stimulated scattering processes is thus essential for such applications as inertial confinement fusion and laser-plasma …

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The Cobden-Chevalier Effect: Evaluating The Causal Effect Of The Most Favoured Nation Clause In Presence Of Network Interdependence, Luca De Benedictis, Silvia Nenci Dec 2013

The Cobden-Chevalier Effect: Evaluating The Causal Effect Of The Most Favoured Nation Clause In Presence Of Network Interdependence, Luca De Benedictis, Silvia Nenci

Luca De Benedictis

The purpose of this work is to evaluate the causal effect of the Network of the Cobden-Chevalier Treaties including the Most Favoured Nation (MFN) clause on trade flows of countries in the second half of the 19th century. This paper contributes to the literature on the topic in several ways. First, it applies up-to-date quantitative methods (i.e., nonparametric matching technique) to the study of historical phenomena. These methods permit to estimate the average MFN effect (the ``treatment") on the treated group of countries in terms of bilateral trade flows (the ``outcome"), rebalancing the control group without imposing any functional relationship …

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Intrinsic Delocalization During The Decay Of Excitons In Polymeric Solar Cells, Thomas F. George, W. Chen, D. Jiang, R. Chen, S. Li Dec 2013

Intrinsic Delocalization During The Decay Of Excitons In Polymeric Solar Cells, Thomas F. George, W. Chen, D. Jiang, R. Chen, S. Li

Thomas George

In bulk heterojunction polymer solar cells, external photoexcitation results in localized excitons in the polymer chain. After hot exciton formation and subsequent relaxation, the dipole moment drives the electron to partially transfer to extended orbitals from the original localized ones, leading to self-delocalization. Based on the dynamic fluorescence spectra, the delocalization of excitons is revealed to be an intrinsic property dominated by exciton decay, acting as a bridge for the exciton to diffuse in the polymeric solar cell. The modification of the dipole moment enhances the efficiency of polymer solar cells.

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Continuum Polarization In Circumstellar Media, Richard Ignace Dec 2013

Continuum Polarization In Circumstellar Media, Richard Ignace

Richard Ignace

See http://www.asu.cas.cz/~wg2prague/

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The Sen Limit, Adrian Clingher, Ron Donagi, Martijn Wijnholt Dec 2013

The Sen Limit, Adrian Clingher, Ron Donagi, Martijn Wijnholt

Adrian Clingher

F -theory compactifications on elliptic Calabi-Yau manifolds may be related to IIb compactifications by taking a certain limit in complex structure moduli space, introduced by A. Sen. The limit has been characterized on the basis of SL(2,Z) monodromies of the elliptic fibration. Instead, we introduce a stable version of the Sen limit. In this picture the elliptic Calabi-Yau splits into two pieces, a P1-bundle and a conic bundle, and the intersection yields the IIb space-time.We get a precise match between F-theory and perturbative type IIb. The correspondence is holographic, in the sense that physical quantities seemingly spread in the bulk …

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Climate Change Adaptation And Water In Semi-Arid Regions: A Case Study Of The Limpopo River Basin, Stanley Mubako Dec 2013

Climate Change Adaptation And Water In Semi-Arid Regions: A Case Study Of The Limpopo River Basin, Stanley Mubako

Stanley Mubako

No abstract provided.

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Adaptive Generalized Crowding For Genetic Algorithms, Ole J. Mengshoel, Severinio Galan, Antonio De Dios Dec 2013

Adaptive Generalized Crowding For Genetic Algorithms, Ole J. Mengshoel, Severinio Galan, Antonio De Dios

Ole J Mengshoel

The genetic algorithm technique known as crowding preserves population diversity by pairing each offspring with a similar individual in the current population (pairing phase) and deciding which of the two will survive (replacement phase). The replacement phase of crowding is usually carried out through deterministic or probabilistic crowding, which have the limitations that they apply the same selective pressure regardless of the problem being solved and the stage of genetic algorithm search. The recently developed generalized crowding approach introduces a scaling factor in the replacement phase, thus generalizing and potentially overcoming the limitations of both deterministic and probabilistic crowding. A …

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Recentering The Humanities, Mellon Grant For “Through The Looking Glass: The Science Of Art...Or The Art Of Science", Crystal Boyce, Karen Schmidt, Gabe Spalding Dec 2013

Recentering The Humanities, Mellon Grant For “Through The Looking Glass: The Science Of Art...Or The Art Of Science", Crystal Boyce, Karen Schmidt, Gabe Spalding

Crystal Boyce

This program proposes to bring together the disciplines of art, theatre, physics, and chemistry as represented through the works of Argonne scientists and how their discoveries have advanced the humanities.

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Characterization Of Large Area, Thick, And Segmented Silicon Detectors For Neutron Β-Decay Experiments, Americo Salas-Bacci, Patrick L. Mcgaughey, Stephan Baeßler, Leah Broussard, Mark F. Makela, J. Mirabal, Robert W. Pattie, Dinko Počanić, Sky K.L. Sjue, Seppo I. Penttila, Wesley S. Wilburn, Albert R. Young, B.A. Zeck, Zhehui Wang Dec 2013

Characterization Of Large Area, Thick, And Segmented Silicon Detectors For Neutron Β-Decay Experiments, Americo Salas-Bacci, Patrick L. Mcgaughey, Stephan Baeßler, Leah Broussard, Mark F. Makela, J. Mirabal, Robert W. Pattie, Dinko Počanić, Sky K.L. Sjue, Seppo I. Penttila, Wesley S. Wilburn, Albert R. Young, B.A. Zeck, Zhehui Wang

Robert W. Pattie Jr.

The “Nab” and “UCNB” collaborations have proposed to measure the correlation parameters in neutron β-decay at Oak Ridge and Los Alamos National Laboratory, using a novel detector design. Two large area, thick, hexagonal-segmented silicon detectors containing 127 pixels per detector will be used to detect the proton and electron from neutron decay. Both silicon detectors are connected by magnetic field lines of a few Tesla field strength, and set on an electrostatic potential, such that protons can be accelerated up to 30 keV in order to be detected. Characteristics of the detector response to low energy conversion electrons and protons from …

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Bis(2-Nitrophenyl)Methane, Daron E. Janzen, Laura E. Crepeau, Benjamin D. Hageseth, James W. Wollack Dec 2013

Bis(2-Nitrophenyl)Methane, Daron E. Janzen, Laura E. Crepeau, Benjamin D. Hageseth, James W. Wollack

Daron E Janzen, Ph.D.

No abstract provided.

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Crystal Structures Of Bis[2-(Diphenylphosphinothioyl) Phenyl] Ether And Bis{2-[Diphenyl(Selanylidene)- Phosphanyl]Phenyl} Ether, Daron E. Janzen, Arianna M. Kooyman, Kayla A. Lange Dec 2013

Crystal Structures Of Bis[2-(Diphenylphosphinothioyl) Phenyl] Ether And Bis{2-[Diphenyl(Selanylidene)- Phosphanyl]Phenyl} Ether, Daron E. Janzen, Arianna M. Kooyman, Kayla A. Lange

Daron E Janzen, Ph.D.

No abstract provided.

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1-Phenyl­Piperazine-1,4-Diium Tetra­Chlorido­Cobalt(Ii), Abdelhamid C. Dhieb, Daron E. Janzen, Mohamed Rzaigui, Wajda S. Sta Dec 2013

1-Phenyl­Piperazine-1,4-Diium Tetra­Chlorido­Cobalt(Ii), Abdelhamid C. Dhieb, Daron E. Janzen, Mohamed Rzaigui, Wajda S. Sta

Daron E Janzen, Ph.D.

No abstract provided.

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Crystal Structures Of 2,6-Bis[(1h-1,2,4-Triazol-1-Yl)- Methyl]Pyridine And 1,1-[Pyridine-2,6-Diylbis- (Methylene)]Bis(4-Methyl-1h-1,2,4-Triazol-4-Ium) Iodide Triiodide, Marites A. Guino-O, Matthew J. Folstad, Daron E. Janzen Dec 2013

Crystal Structures Of 2,6-Bis[(1h-1,2,4-Triazol-1-Yl)- Methyl]Pyridine And 1,1-[Pyridine-2,6-Diylbis- (Methylene)]Bis(4-Methyl-1h-1,2,4-Triazol-4-Ium) Iodide Triiodide, Marites A. Guino-O, Matthew J. Folstad, Daron E. Janzen

Daron E Janzen, Ph.D.

No abstract provided.

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Trichlorido(1-Ethylpiperazin-1-Ium)-Cobalt(Ii), Abdelhamid C. Dhieb, Daron E. Janzen, Mohamed Rzaigui, Wajda S. Sta Dec 2013

Trichlorido(1-Ethylpiperazin-1-Ium)-Cobalt(Ii), Abdelhamid C. Dhieb, Daron E. Janzen, Mohamed Rzaigui, Wajda S. Sta

Daron E Janzen, Ph.D.

No abstract provided.

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Standoff Methods For The Detection Of Threat Agents: A Review Of Several Promising Laser-Based Techniques, J. Bruce Johnson, Susan D. Allen, Jonathan Merten, Lewis Johnson, Daniel Pinkham, Scott Reeve Dec 2013

Standoff Methods For The Detection Of Threat Agents: A Review Of Several Promising Laser-Based Techniques, J. Bruce Johnson, Susan D. Allen, Jonathan Merten, Lewis Johnson, Daniel Pinkham, Scott Reeve

Scott Reeve

No abstract provided.

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Spatial Epidemiology And Climatic Predictors Of Paediatric Dengue Infections Captured Via Sentinel Site Surveillance, Phnom Penh Cambodia 2011–2012, Andrew A. Lover, Philippe Buchy, Anne Rachline, Duch Moniboth, Rekol Huy, Chour Y. Meng, Yee Sin Leo, Kdan Yuvatha, Ung Sophal, Ngan Chantha, Bunthin Y, Veasna Duong, Sophie Goyet, Jeremy Brett, Arnaud Tarantola, Philippe Cavailler Dec 2013

Spatial Epidemiology And Climatic Predictors Of Paediatric Dengue Infections Captured Via Sentinel Site Surveillance, Phnom Penh Cambodia 2011–2012, Andrew A. Lover, Philippe Buchy, Anne Rachline, Duch Moniboth, Rekol Huy, Chour Y. Meng, Yee Sin Leo, Kdan Yuvatha, Ung Sophal, Ngan Chantha, Bunthin Y, Veasna Duong, Sophie Goyet, Jeremy Brett, Arnaud Tarantola, Philippe Cavailler

Andrew Lover

Background
Dengue is a major contributor to morbidity in children aged twelve and below throughout Cambodia; the 2012 epidemic season was the most severe in the country since 2007, with more than 42,000 reported (suspect or confirmed) cases.
Methods
We report basic epidemiological characteristics in a series of 701 patients at the National Paediatric Hospital in Cambodia, recruited during a prospective clinical study (2011–2012). To more fully explore this cohort, we examined climatic factors using multivariate negative binomial models and spatial clustering of cases using spatial scan statistics to place the clinical study within a larger epidemiological framework.
Results
We …

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Retention And Risk Factors For Attrition In A Large Public Health Art Program In Myanmar: A Retrospective Cohort Analysis, Aye Thida, Sai Thein Than Tun, Sai Ko Ko Zaw, Andrew A. Lover, Philippe Cavailler, Jennifer Chunn, Mar Mar Aye, Par Par, Kyaw Win Naing, Kaung Nyunt Zan, Myint Shwe Shwe, Thar Tun Kyaw, Zaw Htoon Waing, Philippe Clevenbergh Dec 2013

Retention And Risk Factors For Attrition In A Large Public Health Art Program In Myanmar: A Retrospective Cohort Analysis, Aye Thida, Sai Thein Than Tun, Sai Ko Ko Zaw, Andrew A. Lover, Philippe Cavailler, Jennifer Chunn, Mar Mar Aye, Par Par, Kyaw Win Naing, Kaung Nyunt Zan, Myint Shwe Shwe, Thar Tun Kyaw, Zaw Htoon Waing, Philippe Clevenbergh

Andrew Lover

Background

The outcomes from an antiretroviral treatment (ART) program within the public sector in Myanmar have not been reported. This study documents retention and the risk factors for attrition in a large ART public health program in Myanmar.

Methods

A retrospective analysis of a cohort of adult patients enrolled in the Integrated HIV Care (IHC) Program between June 2005 and October 2011 and followed up until April 2012 is presented. The primary outcome was attrition (death or loss-follow up); a total of 10,223 patients were included in the 5-year cumulative survival analysis. Overall 5,718 patients were analyzed for the risk …

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Note On The Origin Of The Madagascar Strain Of Plasmodium Vivax, Andrew A. Lover Dec 2013

Note On The Origin Of The Madagascar Strain Of Plasmodium Vivax, Andrew A. Lover

Andrew Lover

Dear Sir:
Recent studies have established the potential for strains of Plasmodium vivax in Madagascar to infect Duffy-negative populations,1 and polymerase chain reaction (PCR)-based screening suggests a previously unrecognized burden of this parasite in sub-Saharan Africa.2
There is a dearth of data concerning any P. vivax parasites from Africa; however, one of the most widely studied strains used during the malariotherapy era was the Madagascar strain, used at the Horton Hospital research site in the UK from 1923 to ca. 1970. This isolate has been the subject of extensive studies,3,4 but there has been considerable …

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Demographic And Spatial Predictors Of Anemia In Women Of Reproductive Age In Timor-Leste: Implications For Health Program Prioritization, Andrew A. Lover, Mikael Hartman, Kee Seng Chia, David L. Heymann Dec 2013

Demographic And Spatial Predictors Of Anemia In Women Of Reproductive Age In Timor-Leste: Implications For Health Program Prioritization, Andrew A. Lover, Mikael Hartman, Kee Seng Chia, David L. Heymann

Andrew Lover

Anemia is a significant risk factor for poor health outcomes for both the mother and neonate; however, the determinants of anemia in many epidemiological settings are poorly understood. Using a subset of a nationally representative cluster survey (2010 Demographic and Health Survey) in combination with other non-contemporaneous survey data, the epidemiology of anemia among women of reproductive age in Timor-Leste has been explored. Logistic regression was used to identify risk factors, population-level impacts were estimated as population attributable fractions and spatial analytics were used to identify regions of highest risk. The DHS survey found that ∼21% of adult women in …

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The Distribution Of Incubation And Relapse Times In Experimental Human Infections With The Malaria Parasite Plasmodium Vivax, Andrew A. Lover, Xiahong Zhao, Zheng Gao, Richard J. Coker, Alex R. Cook Dec 2013

The Distribution Of Incubation And Relapse Times In Experimental Human Infections With The Malaria Parasite Plasmodium Vivax, Andrew A. Lover, Xiahong Zhao, Zheng Gao, Richard J. Coker, Alex R. Cook

Andrew Lover

Background
The distributions of incubation and relapse periods are key components of infectious disease models for the malaria parasite Plasmodium vivax; however, detailed distributions based upon experimental data are lacking.
Methods
Using a range of historical, experimental mosquito-transmitted human infections, Bayesian estimation with non-informative priors was used to determine parametric distributions that can be readily implemented for the incubation period and time-to-first relapse in P. vivax infections, including global subregions by parasite source. These analyses were complemented with a pooled analysis of observational human infection data with infections that included malaria chemoprophylaxis and long-latencies. The epidemiological impact of these …

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Local Perceptions Of Tibetan Village Sacred Forests In Northwest Yunnan, Jodi Brandt, Teri Allendorf Dec 2013

Local Perceptions Of Tibetan Village Sacred Forests In Northwest Yunnan, Jodi Brandt, Teri Allendorf

Jodi Brandt

No abstract provided.

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