Vertical specialization and the changing nature of world trade

A major feature of globalization has been the enormous increase in international flows of goods and services: countries are now trading much more with each other. In this article, the authors demonstrate the greater role vertical specialization is playing in these increased flows. Vertical specialization occurs when a country uses imported intermediate parts to create a good it later exports--that is, the country links sequentially with other countries to produce a final good. Deriving evidence from four case studies as well as OECD input-output tables, the authors reveal that vertical specialization has accounted for a large and increasing share of international trade over the last several decades. They also note that because the trends encouraging vertical specialization--lower trade barriers and improvements in transportation and communications technologies--are likely to continue, this type of international trade should become even more prevalent in the next century.International trade

Male mice emit distinct ultrasonic vocalizations when the female leaves the social interaction arena.

Adult male mice emit large number of complex ultrasonic vocalizations (USVs) when interacting with adult females. Call numbers and call categories differ greatly among inbred mouse strains. Little is known about USV emissions when the social partner departs. To investigate whether call repertoires and call rates are different when the male is interacting with a female and after the removal of the female, we designed a novel male-female social interaction test in which vocalizations were recorded across three phases. During phase 1, the male subject freely interacts with an unfamiliar estrus female mouse in a clean cage for 5 min. During phase 2, the female is removed while the male remains in the cage for 3 min. During phase 3, the same female is returned to the cage to rejoin the male subject mouse for 3 min. C57BL/6J (B6), FVB.129P2-Pde6b(+) Tyr(c-ch)/Ant (FVB), and BTBR T+ tf/J (BTBR) male subject mice were tested in this paradigm. All three strains emitted USVs during their initial interaction with the female partner. When the female was reintroduced in phase 3, numbers of USVs were similar to the initial introductory phase 1. Strain comparisons indicated fewer calls in pairs of BTBR males and stimulus females than in pairs of B6 males and stimulus females and pairs of FVB males and stimulus females. In the absence of the female, all FVB males vocalized, while only one third of B6 males and one third of BTBR males vocalized. In all three strains, changes in call category repertoires were detected after the female was removed. Call categories reverted to the phase 1 pattern when the female was returned in phase 3. Present findings indicate that males of commonly used inbred strains emit USVs when a partner female leaves the testing arena, suggesting that removing a salient social stimulus may be a unique approach to elicit USVs from mice. Our three-phase paradigm may also be useful for studying attention to social cues, and qualitative differences in vocalizations when a social partner is present vs. suddenly absent

Nearest neighbor vector analysis of sdss dr5 galaxy distribution

We present the Nearest Neighbor Distance (NND) analysis of SDSS DR5 galaxies. We give NND results for observed, mock and random sample, and discuss the differences. We find that the observed sample gives us a significantly stronger aggregation characteristic than the random samples. Moreover, we investigate the direction of NND and find that the direction has close relation with the size of the NND for the observed sample.Comment: Natural Science, Vol.5, No.1 in January 201

Learning Convolutional Networks for Content-weighted Image Compression

Lossy image compression is generally formulated as a joint rate-distortion optimization to learn encoder, quantizer, and decoder. However, the quantizer is non-differentiable, and discrete entropy estimation usually is required for rate control. These make it very challenging to develop a convolutional network (CNN)-based image compression system. In this paper, motivated by that the local information content is spatially variant in an image, we suggest that the bit rate of the different parts of the image should be adapted to local content. And the content aware bit rate is allocated under the guidance of a content-weighted importance map. Thus, the sum of the importance map can serve as a continuous alternative of discrete entropy estimation to control compression rate. And binarizer is adopted to quantize the output of encoder due to the binarization scheme is also directly defined by the importance map. Furthermore, a proxy function is introduced for binary operation in backward propagation to make it differentiable. Therefore, the encoder, decoder, binarizer and importance map can be jointly optimized in an end-to-end manner by using a subset of the ImageNet database. In low bit rate image compression, experiments show that our system significantly outperforms JPEG and JPEG 2000 by structural similarity (SSIM) index, and can produce the much better visual result with sharp edges, rich textures, and fewer artifacts

Quantitative Verification of Opacity Properties in Security Systems

Preprin

Verifying Opacity Properties in Security Systems

We delineate a methodology for the specification and verification of flow security properties expressible in the opacity framework. We propose a logic, opacTL, for straightforwardly expressing such properties in systems that can be modelled as partially observable labelled transition systems. We develop verification techniques for analysing property opacity with respect to observation notions. Adding a probabilistic operator to the specification language enables quantitative analysis and verification. This analysis is implemented as an extension to the PRISM model checker and illustrated via a number of examples. Finally, an alternative approach to quantifying the opacity property based on entropy is sketched

Information Needs and Sources of Maasai Pastoralists at Orkesumet in Simanjiro District Manyara Region -Tanzania

Abstract Purpose: This paper reports a study, which examined the specific information needs and sources of Maasai pastoralists at Orkesumet area in Simanjiro District, Manyara -Tanzania Design/methodology/approach: The study used pragmatism paradigm which is a mixed method approach. Simple random sampling was used to select 40 respondents from the five villages (Mukumbi, Naibor-enderit, Narosoito, Orkirung’urung’ and Endonyengijape. Purposive sampling was used to select clan leaders (Ilaigwanak and Ingopir), two from each of the five villages forming ten purposively selected respondents. Questionnaire, interview schedule, and observation were designed to extract information from respondents. Findings: The findings of the study showed that, Maasai practicing pure pastoralism had different needs from those who practice agro-pastoralism. Traditional leaders and extension officers were regarded as the reliable sources of information. Mobile phones were preferred as a source of information but facing challenges. Acquaintance and family members were acknowledged as reliable sources of information. Maasai pastoralist face challenges in the use of information technology due to their low level of educational and inadequate formal sources of information. Practical implications – The authors anticipates that this study will act as an eye opener to the United Republic of Tanzania government and non-government organizations to think of providing appropriate reliable sources of information to Maasai pastoralists so that their contribution can be seen in the socio-economic development of the country. Originality/value – Several studies have been conducted on information needs and sources for different tribes in Tanzania. However, none of these studies have been conducted on Maasai pastoralist. This study is expected to serve as a stepping-stone for further studies on this neglected tribe in socio-economic activities in Tanzania

Squeeziness: An information theoretic measure for avoiding fault masking

Copyright @ 2012 ElsevierFault masking can reduce the effectiveness of a test suite. We propose an information theoretic measure, Squeeziness, as the theoretical basis for avoiding fault masking. We begin by explaining fault masking and the relationship between collisions and fault masking. We then define Squeeziness and demonstrate by experiment that there is a strong correlation between Squeeziness and the likelihood of collisions. We conclude with comments on how Squeeziness could be the foundation for generating test suites that minimise the likelihood of fault masking

Fermi surface with Dirac fermions in CaFeAsF determined via quantum oscillation measurements

Despite the fact that 1111-type iron arsenides hold the record transition temperature of iron-based superconductors, their electronic structures have not been studied much because of the lack of high-quality single crystals. In this study, we completely determine the Fermi surface in the antiferromagnetic state of CaFeAsF, a 1111 iron-arsenide parent compound, by performing quantum oscillation measurements and band-structure calculations. The determined Fermi surface consists of a symmetry-related pair of Dirac electron cylinders and a normal hole cylinder. From analyses of quantum-oscillation phases, we demonstrate that the electron cylinders carry a nontrivial Berry phase $\pi$. The carrier density is of the order of 10$^{-3}$ per Fe. This unusual metallic state with the extremely small carrier density is a consequence of the previously discussed topological feature of the band structure which prevents the antiferromagnetic gap from being a full gap. We also report a nearly linear-in-$B$ magnetoresistance and an anomalous resistivity increase above about 30 T for $B \parallel c$, the latter of which is likely related to the quantum limit of the electron orbit. Intriguingly, the electrical resistivity exhibits a nonmetallic temperature dependence in the paramagnetic tetragonal phase ($T >$ 118 K), which may suggest an incoherent state. Our study provides a detailed knowledge of the Fermi surface in the antiferromagnetic state of 1111 parent compounds and moreover opens up a new possibility to explore Dirac-fermion physics in those compounds.Comment: 11 pages, 7 figures, 1 tabl