A study of the seasonal dynamics of grassland growth rates in Inner Mongolia based on AVHRR data and a light‐use efficiency model

Growth rate data for different pastures could provide important reference data for developing rotation grazing plans, for hay production, and for forage replenishment. Based on AVHRR NDVI data and a light‐use efficiency (LUE) model, we estimated absorbed photosynthetically active radiation and LUE (ε) by integrating air and soil temperature, precipitation and total solar radiation time series data from 1986 to 1999, and calculated the absolute growth rate (AGR) and cumulative absolute growth rate (CAGR) of aboveground biomass in each growing season in China's Inner Mongolia region. AGR and CAGR estimated by the LUE model were validated using monthly growth data obtained for the vegetation in desert steppe, typical steppe, and meadow steppe ecosystems from 1986 to 1995. The LUE model provided sufficiently good simulation accuracy that its use should permit improved livestock feed management in the study area. From 1986 to 1999, average CAGR of steppe vegetation during the growing season increased quickly in June and July, reached a maximum in July and August, and declined in September. In 1999, AGR reflected the pattern of seasonal vegetation dynamics during the growing season.     

Evaluating Algeria’s social and economic development using a series of night-time light images between 1992 to 2012

ABSTRACT

After social and economic problems, Algeria regained its night-time light (NL) brightness as this analysis of space-borne images shows. We evaluate the advancement of artificial light sources and the socioeconomic development between 1992 to 2012 for all 48 provinces. Image calibration improved the consistency and comparability of the DMSP-OLS data. Light detected from gas flaring has been separated to focus on light from human settlements. We then estimated the relationship between night-time light and selected socioeconomic parameters (SEP). Night-time light growth (NLG) and night-time light annual growth (NLAG) indices are calculated at the national, regional and provincial level. Considering the Oil price crash and the Algerian Civil Concord, we take a detailed look at these historic events in Algeria. Our main findings are: (A) The total night-time light (TNL) for human settlements grew nationwide by 128%, (B) night-time light data correlates with socioeconomic parameters such as population, and electric power consumption, (C) the oil price crash resulted in slower night-time light growth, while the Algerian Civil Concord and the end of the crises led to increased TNL, (D) because of government investment, the High Plateaus are the fastest growing region since the end of the crises, (E) space-borne night-time light data can consistently fill the information gap when data from official sources are not available. Government and policy-making bodies may benefit from the presented findings allowing them to oversee and address provincial inequalities and economic development.     

An NDVI-data harmonic analysis to study deforestation in Peru’s Tahuamanu province during 2001–2011

We investigate the spatio-temporal variability of normalized difference vegetation index (NDVI) associated with deforestation in four zones in southeastern Peru (Madre de Dios Region): (1) an area comprising part of the Tahuamanu province (mainly, but it also comprises a small part of Tambopata province), (2) a part of the Tahuamanu watershed, (3) surrounding areas of Iñapari and Iberia towns, and (4) another area in the Iñapari district which we labelled as Iñapari-B. We have utilized three statistical tools: the empirical orthogonal function (EOF), Fourier analysis, and wavelet analysis. EOF was used to obtain the maximum variability of the NDVI-anomaly spatial patterns and also their associated temporal variability as time series. Fourier analysis was used to determine the periodicities on the EOF pattern and associated them to deforestation in the region. Wavelet analysis was used to detect the maximum variability of the phenomena and to portray their statistical significance along the period of study and so identify when the maxima happen. From the results obtained, in Zone I, we have found a 2-month deforestation periodicity with major peaks in 2004 and 2009; in Zone II, the periodicity is about 1.8 months, with a maximum peak in 2009; in Zone III, the periodicity is 2.4 months with the highest peak in 2009; in Zone IV, the high-frequency periodicity is about 2.8 months with the main peaks in 2000, 2003, and 2004.     

The open question of the relation between square matrix’s eigenvalues and its similarity matrix’s singular values in linear discrete system

In linear discrete system, we often need to utilize similarity transformation to extend the solution ranges of its corresponding discrete matrix equations. Consequently, how to choose the similarity transformation matrix remains an open question in recent years. In this paper, by applying the theory of matrix’s Jordan canonical form and the related properties of nonnegative matrices, we construct the similarity transformation matrix of some special similarity transformation, then present a necessary and sufficient condition and a corresponding algorithm, thus solve the open question totally.     

Situating the “music of” households and firemen in semi-open spaces: contribution to the analysis of collective activity’s spatio-temporal dynamics

Cognition, Technology & Work - Examining different team dynamics and understanding collective activities in home environments are two important challenges for ergonomics and its related fields....     

A switched optimal control approach to reduce transferring time,energy consumption,and residual vibration of payload’s skew rotation in crane systems

In this paper, nonlinear optimal control schemes are proposed to reduce transferring time, energy consumption, and residual vibration for the payload’s skew rotation process of crane systems. The main contribution of this paper is to reduce the energy consumption without trading-off the sub-optimal transferring time. The novel idea is to use an electro-mechanical clutch to intelligently disengage the connection between the motor and the payload during the motion such that the payload can continue rotating only by its own momentum. As a result, a switched optimal control problem must be realized. Two solutions, namely particular and general schemes are proposed in the paper, where physical constraints of the actuator including bounded velocity and bounded acceleration are explicitly taken into account. Both simulation and experimental results are provided to prove the effectiveness of the proposed optimal control systems. The established schemes can be directly applied to transfer the payload to a desirable skew orientation without any residual oscillation, or can be utilized as a sub-optimal-time reference trajectory planner of the skewing control module in either overhead or rotary crane systems. Furthermore, the hybrid rotation process presented in this paper, which is driven by the engaging/disengaging event of the clutch, can be served as a theoretical benchmark for any newly established switched optimal control method.     

Finding meaning in a celebrity’s death: The relationship between parasocial attachment,grief, and sharing educational health information related to Robin Williams on social network sites

Celebrity health events can have a positive effect on public health education and awareness, in part because people spread health information related to the celebrity on social network sites. This may be particularly true in the event of celebrity deaths or other tragedies, when social network sites provide a convenient, public space to connect with others to mourn. However, little is understood about the circumstances that encourage health information sharing following these events. Using a Mechanical Turk sample (N = 281), this study employed a questionnaire to examine the role of parasocial attachment to Robin Williams and experienced grief following his suicide in explaining health information sharing on social network sites (i.e., sharing information about clinical depression, suicide prevention, substance abuse treatment, and Parkinson’s disease). Grief mediated the effect of parasocial attachment on health information sharing, but a moderated mediation analysis revealed that grief motivated health education on social network sites only for individuals who were coping by trying to find positive meaning in his death.     

Author’s reply to a discussion by Gengdong Cheng and Xiaofeng Liu of the review article “On symmetry and non-uniqueness in exact topology optimization” by George I. N. Rozvany (2011, Struct Multidisc Optim 43:297–317)

It is explained in this reply that the author fully agrees with the writers of the discussion, because findings of similar nature were introduced already in the original article. Further counter-examples demonstrating the range of validity of the author’s propositions are also presented.