Tier 2 Research Articles

Trends in player body mass at men’s and women’s Rugby World Cups: a plateau in body mass and differences in emerging rugby nations

ObjectivesThis study assessed the mass of international rugby players in the men’s and women’s Rugby World Cups between 1991 and 2019. The objective was to quantify changes in mass of...

Online Algorithm for Leasing Wireless Channels in a Three-Tier Spectrum Sharing Framework

The three-tier spectrum sharing framework (3-TSF) is a spectrum sharing model adopted by the Federal Communications Commission. According to this model, under-utilized federal spectrum like the Citizens Broadband Radio Service band is released for shared use where the highest preference is given to Tier-1 followed by Tier-2 (T2) and then Tier-3 (T3). In this paper, we study how a wireless operator, who is interested in maximizing its profit, can strategically operate as a T2 and/or a T3 user. T2 is characterized by paid but ”almost” guaranteed and interference-free channel access while T3 access is free but has the lesser guarantee and also faces channel interference. So the operator has to optimally decide between paid but better channel quality and free but uncertain channel quality. Also, the operator has to make these decisions without knowing future market variables like customer demand or channel availability. The main contribution of this paper is a deterministic online algorithm for leasing channels that has finite competitive ratio, low time complexity, and that does not rely on the knowledge of market statistics. Such algorithms are desirable in the early stages of the deployment of 3-TSF because the knowledge of market statistics may be rather inaccurate. We use tools from the ski-rental literature to design the online algorithm. The online optimization problem for leasing channels is a novel generalization of the ski-rental problem. We, therefore, make fundamental contributions to the ski-rental literature, the applications of which extend beyond this paper. We also conduct simulations using synthetic traces to compare our online algorithm with the benchmark and state-of-the-art algorithms.

Greenhouse gas inventories: Deriving soil organic carbon change factors and assessing soil depth relevance in Argentinean Semiarid Chaco

Soil organic carbon (SOC) is the main terrestrial carbon (C) reservoir. Land use change has depleted SOC stocks and released large amounts of C dioxide (CO2). Thus, the development of reliable tools for SOC stock monitoring at large scale is fundamental to face climate change. Argentinean Semiarid Chaco (ASC) is a deforestation hotspot, but CO2 emissions from soil has been barely assessed. Deforested area was converted into cropland or grassland. We used empirical data to model SOC stocks under native forest (SOCref) and the RothC model to estimate SOC stock change factors under cropland (Fc) and grasslands (Fg) in the ASC. These SOCref's and stock change factors were applied in a Tier 2 (T2) C inventory, following the Intergovernmental Panel on Climate Change (IPCC) proposal. We used SOC vertical distribution models to estimate SOC stock at 0–100 cm soil depth from estimated SOC stocks at 0–30 cm, the default soil depth of IPCC C inventory method. The T2 was run for 1976 through 2012 and under three hypothetical land use change scenarios for 2012 through 2032. The scenarios were: i) land use change ceases, ii) land use change rate is the half of 1996–2012 land use change rate, and iii) land use change rate remains as in 1996–2012. Estimated average SOCref stock at 0–30 cm soil depth was 40 Mg C ha−1 and varied between 35 and 51 Mg C ha−1. Cropland was the main fate of deforested area and the land use with lower SOC stocks. Stock change factors and SOC stocks estimated with T2 were within the range of the empirical data reported in the ASC. However, research about SOC dynamics and land use change is incipient in the ASC and more empirical information is needed to validate T2 estimations. Deforestation in the ASC leads to high CO2 emissions from soil and the only scenario in which those emissions would be reduced is with deforestation cessation. Soil depth considered in greenhouse gas inventories is 0–30 cm, and this strongly underestimates CO2 emissions. We demonstrated that this limitation could be overcome by using SOC vertical distribution models to estimate deep SOC stock (up to 1 m) from estimated surface SOC stock. Hence, these models could be used to improve CO2 estimations from SOC inventories.

Tier 2 Capital Instruments under Basel III: A Sharīʿah Viewpoint

Abstract Basel III has redefined the criteria for regulatory capital instruments. Accordingly, Islamic banking institutions (IBIs) have to consider the issuance of instruments that would meet both the objectives of Basel III and Sharīʿah requirements. This research particularly aims to compare the regulatory requirements for issuing Tier-2 (T2) capital instruments as defined by Basel III, Bank Negara Malaysia (BNM) and IFSB-15. In this regard, the research examines the Sharīʿah issues related to subordination and conversion arising in exchange-based contracts (such as murābaḥah and iǧārah ṣukūk) and equity-based contracts (such as muḍārabah and wakālah ṣukūk). The study relies on library research to collect secondary data in the form of classical works of Islamic jurisprudence, analyses such work and links it with the present day regulatory requirements. The study finds that there are Sharīʿah concerns over the use of exchange-based contracts. However, the use of convertible muḍārabah and wakālah ṣukūk could be justified.

Comparison of models for estimating methane emission factor for enteric fermentation of growing-finishing Hanwoo steers.

The methodology provided by the Intergovernmental Panel on Climate Change (IPCC) guidelines is widely used for estimating enteric methane (CH4) production by cattle. No attempt other than the default values in the IPCC Tier 1 has been made for estimating CH4 emission from Hanwoo, a dominant beef species in Korea raised in a unique feeding system. The objective of this study was to compare models for estimating the CH4 emission factor (MEF; kg CH4/head/year) for enteric fermentation in Hanwoo steers. The MEF was estimated based on Korea- and Hanwoo-specific data obtained from the literature using several models. The models include the IPCC Tier 1 (T1), the IPCC Tier 2 method (T2), the IPCC Tier 2 methodology with actual dry matter intake (T2DMI), and the Japanese Tier 3 method (JT3). The JT3 was included due to the similarity in the beef cattle production system between the two countries. Estimated MEF using T2 were 43.4, 33.9, and 36.2 kg CH4/head/year for the growing, finishing, and overall period, respectively. The overall MEF estimated using T2 was 23 % lower than the estimate by T1 (47.0 kg CH4/head/year). There were significant differences in the estimated MEF for enteric fermentation of Hanwoo steers among the methods (P < 0.05). The overall MEF estimated by JT3 was 69.1 kg CH4/head/year, which was significantly higher than the estimates by T2 (36.2 kg) and T2DMI (33.5 kg). The JT3 estimated the highest values in all periods possibly due to overestimation of the conversion ratio of feed energy to CH4. No significant difference was found in the overall MEF of Hanwoo steers between T2 and T2DMI. However, T2DMI estimated 8 % higher and 14 % lower MEF than T2 for the growing and finishing period, respectively, mainly because the T2 significantly over-predicts the gross energy intake of Hanwoo steers at the high level of intake. The IPCC default methods have limitations in their use for a feeding systems in non-western countries, and thus development of a country-specific methodology and parameter estimates for enteric CH4 production is required for Hanwoo and other cattle production systems.

Pitfalls in Valuing Hybrid Bonds: Impact of Bank Bailout Regulation on Subordination Component Pricing.

Hybrid securities combine elements of both shares and corporate bonds. A key equity-like feature of hybrid securities is the ability of the issuer to avoid making cash payments in periods of financial stress. Regarding banks as issuers, hybrid bonds may be assigned to either Additional Tier 1 (AT1) or Tier 2 (T2), provided that certain criteria are met.The objective of this research is to propose a pricing model respecting the subordination feature of T2 and AT1 hybrids. The authors undertake the challenge of finding interlinks between senior and subordinated hybrid bonds prices, using a structural approach.Empirical analysis of Banco do Brasil different bond issues characteristic and prices shows that market somehow neglects deferability of coupons and subordination of capital repayments. It results in distortion between the market price and theoretical Merton-model.Tracking down to Brasilian regulation, government policy and systemically importance of Banco do Brasil, investors concluded that government would rather proceed with bailout than let it go bankrupt or bail-in the issued debt. This enables investors to price AT1 hybrids issued by this government-owned bank rather as non-subordinated bonds. The possibility of the bailout makes the modelling of corporate debts more challenging. The authors assessed how big is the impact of the presence of the bailout on subordination component pricing.

Simplified Method for Comparing Emissions in Roundabouts and at Signalized Intersections

An empirically based macroscopic method is presented. It estimates and compares the pollutant emissions generated from signalized intersections and roundabouts. This method was built on a large sample size of real-world second-by-second vehicle trajectories, traffic volumes, and other traffic characteristics collected at signalized intersections and roundabouts in six U.S. states. The basis for predicting and estimating pollutant emissions was the concept of vehicle-specific power. The method enables inclusion of emissions standards and vehicle classes, such as Tier 1 (T1) and Tier 2 (T2) passenger cars (PCs) and passenger trucks (PTs). More than 1,980 vehicle trajectories were analyzed. Traffic variables including intersection capacity, demand-to-capacity ratio ( d/ c), cycle length, green-to-cycle length ratio, signal progression (i.e., arrival type), and number of lanes were included in the model for analysis and comparison between signals and roundabouts. Application of the method to a case study showed that on average under low d/ c (&lt;0.7), roundabouts generated lower emission rates than signalized intersections. As demand approached capacity under high traffic volumes, signalized intersections with favorable progression (i.e., most demand arrived during green phase) generally produced lower emission rates than roundabouts. Signalized intersections with poor progression (i.e., most demand arrived during red phase) generated more emissions than roundabouts. Results also showed that during oversaturation periods (when d/ c &gt; 1), the amount of produced emissions increased steadily in roundabouts but increased a large amount at signals.

Agricultural impact on soil organic carbon content: Testing the IPCC carbon accounting method for evaluations at county scale

Soil organic carbon (SOC) plays a vital role in determining soil quality and health, but also SOC decrease contributes significantly to the increase in atmospheric CO2 concentration. Countries need to quantify their SOC stocks and flows in order to assess their greenhouse gas emissions. To facilitate this, the Intergovernmental Panel on Climate Change has developed a simple carbon accounting method to estimate SOC stocks and flows in response to changes in land use. This method proposes three tiers for SOC change estimation. The higher the tier the greater the accuracy of the estimates, but also the complexity and the need of information. We used the RothC model to derive SOC change factors in order to develop a Tier 2 (T2) method. We applied this T2 and Tier 1 (T1) methods to estimate SOC stocks and flows in five sub regions of the Argentinean Pampa Region between 1900 and 2006. We evaluated T1 and T2 methods performances comparing their estimates against empirical data, at sub region and county scales. At both spatial scales, T1 method showed a poor performance and an important improvement was achieved with T2 method, although its performance varied among spatial scales. At sub region scale, T2 method estimates were very good (R2=0.85), but at county scale the fit was poor (R2=0.46). However, this poor fit may have been due, at least in part, to the quality of the input and validation information of one of the sub regions (Flooding Pampa) since its exclusion of the analysis led to an increase of the R2 up to 0.73. Tier 2 was used to estimate the impact of land use change on SOC. Sub regions with the highest estimated SOC losses were Central Pampa, Southern Pampa – Eastern and Rolling Pampa, with 35%, 28% and 26% average SOC losses, respectively. Given that several conceptual limitations of T1 method were overcome with our simple T2 method, we conclude that T2 method is more realistic to conduct a regional SOC inventory. Besides, our T2 method was developed without using empirical information from field or laboratory studies about SOC change and, therefore, countries that have not enough empirical information available on SOC change associated to land use could derive a similar T2 method.

Significance of experimental studies for assessing adverse effects of endocrine-disrupting chemicals

The U.S. Environmental Protection Agency (USEPA) is developing an endocrine disruptor screening and testing program to detect chemicals that alter hypothalamic-pituitary-gonadal (HPG) function, estrogen, androgen, and thyroid (EAT) hormone synthesis or metabolism and induce androgen (AR) and estrogen (ER) receptor-mediated effects in mammals and other animals. The utility of this approach is based upon the knowledge that mechanisms of endocrine-disrupting chemical (EDC) action are highly conserved at the cellular and molecular levels among vertebrates. Some EDC mechanisms also are shared with invertebrates. High-priority chemicals would be evaluated in a Tier 1 screening (T1S) battery, and chemicals that are positive in T1S would then be tested in Tier 2 (T2). T1S includes in vitro ER and AR receptor binding and/or gene expression, an assessment of steroidogenesis and mammalian (rat) and nonmammalian (fish) in vivo assays. In vivo, the uterotropic assay detects estrogens and antiestrogens, while steroidogenesis, antithyroid activity, antiestrogenicity, and HPG function are assessed in a pubertal female assay. Antiandrogens are detected in the Hershberger assay (weight of androgen-dependent tissues in castrate-immature-male rats). Fish and amphibian assays are also being developed to identify EDCs. Several alternative mammalian in vivo assays have been proposed. Of these, a short-term pubertal male rat assay appears most promising. T1S is designed to be sensitive to EAT activities, but many of the effects detected at the screening level would not be considered adverse, the dosage levels may be high, and the route of administration used may not be the most relevant. However, issues of adversity, dose response, and route(s) of exposure would be resolved in the testing phase. In addition to using an enhanced multigenerational test for Tier 2, an in utero-lactational screening protocol is also being evaluated by USEPA for use in T2 or T1S. For T2, the numbers of endocrine-sensitive end-points and offspring (F1) examined in multigenerational tests need to be expanded for EDCs in a thoughtful manner, based in part upon the results of T1S. In addition, for some chemicals histological examination of 10 adult F1 per sex in only the control and high-dose groups provides inadequate statistical power to detect low-dose lesions induced during development. In these cases, we propose that all the offspring be examined after puberty for gross and histological reproductive abnormalities. Since EDCs, like the phthalates and AR-antagonists, produce characteristic profiles, or syndromes, of adverse effects, data need to be reported in a manner that clearly identifies the proportion of animals displaying one or more of the abnormalities in a syndrome. Consideration should be given to tailoring T2, based on the results of T1S to assure that all of the effects in such chemically induced developmental syndromes are included in the study.