Triangular simultaneous equations model under structural misspecification

Triangular simultaneous equation models are commonly used in econometric analysis to analyse endogeneity problems caused, among others, by individual choice or market equilibrium. Empirical researchers usually specify the simultaneous equation models in an ad hoc linear form; without testing the validity of such specification. In this paper, approximation properties of a linear fit for structural function in a triangular system of simultaneous equations are explored. I demonstrate that, linear fit can be interpreted as the best linear prediction to the underlying structural function in a weighted mean squared (WMSE) error sense. Furthermore, it is shown that with the endogenous variable being a continuous treatment variable, under misspecification, the pseudo-parameter that defines the returns to treatment intensity is weighted average of the Marginal Treatment Effects (MTE) of Heckman and Vytlacil (2001). Misspecification robust asymptotic variance formulas for estimators of pseudo-true parameters are also derived. The approximation properties are further investigated with Monte-Carlo experiments

Resolving genetic relationships in manna group of lichens from genus Aspicilia

As in many lichen-forming fungi, species of Aspicilia genus are widely distributed all over the world, but no reports exist about their phylogenetic relations based on molecular biological methods. In thecurrent study the phylogenetic relations of some Aspicilia species mainly manna group of lichens were investigated. The ITS rDNA sequence information of 12 samples from six species were generated. The samples examined were collected from different provinces of Anatolia and all the sequences were aligned with the other allied groups; Pertusaria sp., Thamnolia sp., Dibaeis sp., Diploschistes sp.,Ochrolechia sp. and Lecanora sp. sequence data obtained from GenBank. The phylogenetic tree obtained by minimum evolution analysis displayed two major branches. One of the branches with itssix members (Aspicilia contorta subsp. contorta, A. contorta subsp. hoffmanniana, Aspicilia hispida, Aspicilia fruticulosa, Aspicilia desertorum Aspicilia calcarea) composed solely of Aspicilia samplesfrom Anatolia. Three of the manna groups of lichens were placed in this branch of the tree. The other related taxa from Ostropomycetidae and Lecanoromycetidae took place in the other branch of the treewith Aspicilia samples from Anatolia. Results displayed that manna group of lichens, although do not represent taxonomical unit tend to form a group especially apperent by the Neigbour Joining analysiswith Anatolian samples. Also the sequence information from Anatolian samples displayed that Aspicilia genus is phylogenetically closer to the orders and families from Ostropomycetidae subclass rather than Lecanoromycetidae which support the placement of Hymeneliaceae within Ostropomycetidae

Heterogeneous Catalysis under pressure - In-situ neutron diffraction under industrial conditions

The present work describes the application of a tubular reactor that allows in-situ neutron diffraction on working catalysts at high pressures. The designed reactor enables the application to a sample of industrially-relevant reaction conditions, i.e., in a temperature range up to 330° C and 60 bar pressure, coupled with online gas-analysis. Application of the cell is demonstrated by ammonia synthesis over a commercial catalyst with diffraction data obtained from the high-resolution powder diffractometer, Echidna, at the Australian Nuclear Science and Technology Organisation, ANSTO

Yeni bir insansız hava aracının (SUAVİ) prototip üretimi ve algılayıcı-eyleyici entegrasyonu

Bu çalısmada, dört-döner rotoru ile helikopter gibi dikine kalkıs ve inis yapabilen aynı zamanda da uçak gibi uzun menzil yatay uçus yeteneğine sahip yeni bir insansız otonom hava aracının mekanik ve aerodinamik tasarımı, karbon kompozit imalatı, algılayıcı eyleyici sistem entegrasyonu ve uçus deneyleri anlatılmıstır. Gelistirilen sistem ve içinde kullanılan algılayıcı eyleyici entegrasyonunun basarımı benzetim ve deneylerle doğrulanmıstır

Tracking the timing of Neotethyan oceanic slab break-off: Geochronology and geochemistry of the quartz diorite porphyries, NE Turkey

The initiation of the break-off of the northern branch of the Neotethyan oceanic lithosphere is an important but poorly understood event in the geology of the Sakarya Zone (SZ) in northeastern Turkey. Although it is well-known that Latest Cretaceous intrusives (~70 Ma) and early Eocene adakitic magmatic rocks are present in the eastern SZ, the outcrops of the early Eocene non-adakitic rocks are very limited, and their tectono-magmatic evolution has not been studied. We describe a small outcrop of non-adakitic quartz diorite porphyry in the Kov area of the Gümüşhane region in northeastern Turkey. The genesis of these porphyries is significant in evaluating the syn- to post-collision-related magmatism. The LA-ICP-MS zircon U-Pb dating revealed that the Kov quartz diorite porphyries (KQDP) formed at ca. 50 Ma, coeval with adakitic rocks, and ~20 Myr later than the slab roll-back-related intrusive rocks. The KQDPs are calc-alkaline in composition and enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in high field strength elements (HFSEs; e.g., Nb, Ta, Ti), with significant negative anomalies of Nb, Ta, and Ti but positive anomalies of Th, U, and Pb. Isotopic compositions of the samples show limited range of variation and slight enrichment of 87Sr/86Sr(t) (0.70489 to 0.70555), εNd(t) (−1.4 to −1.2) with TDM of 1.11 to 1.61 Ga. Pb isotopic ratios of the samples point to an enriched mantle source. They were likely crystallized from the melt that originated from an EM2-type spinel-facies subcontinental lithospheric mantle (SCLM), followed by the fractionation with insignificant crustal assimilation. The SCLM was metasomatically enriched, and the metasomatic agent was likely H2O-rich fluids rather than sediments released from subducting oceanic crust during the Late Cretaceous closure of the Neotethyan oceanic lithosphere. In conjunction with the geological background and previous data, we propose that the generation of the KQDPs resulted from a slab break-off event that caused ascending or infiltration of hot asthenosphere, triggering mantle melting. Such sporadic occurrences of the KQDPs, with coeval adakitic rocks in the SZ, are likely associated with the onset of extensional tectonics due to the earlier stage of slab break-off along the region during the early Eocene period.publishe

Profiler and compiler assisted adaptive I/O prefetching for shared storage caches

I/O prefetching has been employed in the past as one of the mech- anisms to hide large disk latencies. However, I/O prefetching in parallel applications is problematic when multiple CPUs share the same set of disks due to the possibility that prefetches from different CPUs can interact on shared memory caches in the I/O nodes in complex and unpredictable ways. In this paper, we (i) quantify the impact of compiler-directed I/O prefetching - developed originally in the context of sequential execution - on shared caches at I/O nodes. The experimental data collected shows that while I/O prefetching brings benefits, its effectiveness reduces significantly as the number of CPUs is increased; (ii) identify inter-CPU misses due to harmful prefetches as one of the main sources for this re- duction in performance with the increased number of CPUs; and (iii) propose and experimentally evaluate a profiler and compiler assisted adaptive I/O prefetching scheme targeting shared storage caches. The proposed scheme obtains inter-thread data sharing information using profiling and, based on the captured data sharing patterns, divides the threads into clusters and assigns a separate (customized) I/O prefetcher thread for each cluster. In our approach, the compiler generates the I/O prefetching threads automatically. We implemented this new I/O prefetching scheme using a compiler and the PVFS file system running on Linux, and the empirical data collected clearly underline the importance of adapting I/O prefetching based on program phases. Specifically, our pro- posed scheme improves performance, on average, by 19.9%, 11.9% and http://dx.doi.org/10.3% over the cases without I/O prefetching, with independent I/O prefetching (each CPU is performing compiler-directed I/O prefetching independently), and with one CPU prefetching (one CPU is reserved for prefetching on behalf of others), respectively, when 8 CPUs are used. Copyright 2008 ACM

Intrinsic Spin-Orbit Interaction in Graphene

In graphene, we report the first theoretical demonstration of how the intrinsic spin orbit interaction can be deduced from the theory and how it can be controlled by tuning a uniform magnetic field, and/or by changing the strength of a long range Coulomb like impurity (adatom), as well as gap parameter. In the impurity context, we find that intrinsic spin-orbit interaction energy may be enhanced by increasing the strength of magnetic field and/or by decreasing the band gap mass term. Additionally, it may be strongly enhanced by increasing the impurity strength. Furthermore, from the proposal of Kane and Mele [Phys. Rev. Lett. 95, 226801 (2005)], it was discussed that the pristine graphene has a quantized spin Hall effect regime where the Rashba type spin orbit interaction term is smaller than that of intrinsic one. Our analysis suggest the nonexistence of such a regime in the ground state of flat graphene

Levels of selected minerals, nitric oxide, and vitamins in aborted Sakis sheep raised under semitropical conditions

The serum levels of calcium, phosphorus, magnesium, copper, zinc and iron and of nitric oxide, retinol, and β-carotene were determined in Sakiz ewes that had experienced an abortion and in healthy controls. Ten healthy and 25 aborted Sakiz sheep were selected from Afyon zone in western Turkey. Their ages ranged between 2 and 4 years weighing between 40 and 60 kg at the time of experiment. All of the abortions occurred in October. The concentrations of retinol, β-carotene, phosphorus, and zinc were significantly lower and those of calcium and nitric oxide were increased in aborted ewes relative to healthy controls. The serum levels of iron, copper, and magnesium were not significantly different among the two groups. In conclusion, abortion is an important problem in commercially important species of ruminants in many regions in the tropics including of western Turkey. Deficiencies of retinol, β-carotene, phosphorus and zinc, and the increase of calcium and nitric oxide concentration may play an important role in the etiology of abortion in ewes. Prophylactic measures such as vitamin and mineral supplementation may be of help to prevent or reduce the incidence of abortion in sheep