Old Main-Sequence Turnoff Photometry in the Small Magellanic Cloud. I. Constraints on the Star Formation History in Different Fields

We present ground-based B and R-band color-magnitude diagrams (CMDs), reaching the oldest main-sequence turnoffs with good photometric accuracy for twelve fields in the Small Magellanic Cloud (SMC). Our fields, located between ~1 and ~4 degrees from the center of the galaxy, are situated in different parts of the SMC such as the "Wing'' area, and towards the West and South. In this paper we perform a first analysis of the stellar content in our SMC fields through comparison with theoretical isochrones and color functions (CFs). We find that the underlying spheroidally distributed population is composed of both intermediate-age and old stars and that its age composition does not show strong galacto-centric gradients. The three fields situated toward the east, in the Wing region, show very active current star formation. However, only in the eastern field closest to the center do we find an enhancement of recent star formation with respect to a constant SFR(t). The fields corresponding to the western side of the SMC present a much less populated young MS, and the CF analysis indicates that the SFR(t) greatly diminished around 2 Gyr ago in these parts. Field smc0057, the closest to the center of the galaxy and located in the southern part, shows recent star formation, while the rest of the southern fields present few bright MS stars. The structure of the red clump in all the CMDs is consistent with the large amount of intermediate-age stars inferred from the CMDs and color functions. None of the SMC fields presented here are dominated by old stellar populations, a fact that is in agreement with the lack of a conspicuous horizontal branch in all these SMC CMDs. This could indicate that a disk population is ruling over a possible old halo in all the observed fields.Comment: To appear in A

Investigating the unique reactivity of novel HX (X=Cl, Br) reagents with alkenes and alkynes.

The addition of hydrogen halides to carbon-carbon unsaturated systems is a classic synthetic transformation that gives rise to a variety of halogenated products as well as building blocks.1 The different routes to achieve hydrohalogenation make use of the hydrogen halides either in the gaseous form2 or in solution3, or their surrogates4. Only second to dihalogens, hydrogen halides are the most atom efficient source of halogenation. However, hydrogen halides are reactive gases at ambient temperature, posing a major challenge in their application. Handling gaseous hydrogen halide reagents requires expert knowledge and specialized equipment. We have investigated the formulation of environmentally benign organic aprotic hydrogen halide solutions to address this challenge. The properties of these formulations have been investigated in reactions with unsaturated systems. Given that hydrogen bonding may play a role in the formation of stable HX solutions, we sought to screen and investigate various solvents with strong hydrogen bonding capabilities that do not adversely jeopardize the intrinsic properties the HX molecules. The few commercially available aprotic HX-solutions have low concentrations of HX and therefore offer few synthetic advantages.5 The formulation of stable HX solutions with higher concentrations and better reactivity in hydrohalogenation was our goal. Inspired by Laurence et al’s concept of hydrogen bond basicity6 and their classification of organic molecules based on their basicity (pKBHX scale), we found that 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU) formed a stable complex with HF molecules. Our newly formulated solution of hydrogen fluoride in DMPU has exhibited higher reactivity than its predecessors in a wide scope of transformations.7 We are pleased to report novel DMPU solutions of HCl and HBr. The advantages of these solutions are their relatively higher HX concentrations (12.6 M HCl and 10 M HBr) and bench stable over long periods of time compared to the commercially available organic solutions. Another unique quality of these solutions is their compatibility with water and/or base-sensitive reactions. In addition, DMPU is non-nucleophilic, so it won’t compete with halides in nucleophilic reactions. These new organic-based solutions of hydrogen halides have been applied in a metal-free hydrobromination of alkynes8 and a homogenous gold-catalyzed hydrochlorination of alkynes9. In addition, the combination of our new HCl reagent (HCl/DMPU) with sulfoxides forms a unique chlorothiolation system for alkenes with high regioselectivity.10 Under mild and transition-metal-free conditions, dimethylsulfoxide (DMSO) undergoes a one-carbon homologation to afford 4-chloropiperidines from homoallylic amines via a Pummerer fragmentation mechanism. The reactions are scalable and have broad substrate scope

Emotional or Behavioral Disorders

If surveyed across several generations, casual inquirers would not be hard-pressed to discover differing attitudes about current behavior challenges in schools today. While many structures have been established and documents written, one cannot deny the changes in focus that are now required to accommodate new attitudes and behaviors in many children in our public education system. The Individuals with Disabilities Education Act maintains a formal definition of Emotional and Behavioral Disorders (EBD) which led to this disorder being included in the list of IEP-warranted classifications. Children who exhibit symptoms within the listed criteria often are identified as demonstrating predominately externalizing behaviors (the most common) or internalizing behaviors (Heward, 2009). Getting out of seat, yelling, blurting out, hitting, fighting, complaining, excessive arguing, lying, stealing, non-compliance and destruction of property are some examples of externalizing behaviors. Contrarily, internalizing behaviors may include limited peer interactions, daydreaming, fantasies, fear of certain things, frequent complaints of being sick or hurt and feelings of depression (Heward, 2009)

Financial globalization, governance, and the evolution of the home bias

Standard portfolio theories of the home bias are disconnected from corporate finance theories of insider ownership. We merge the two into what we call the optimal ownership theory of the home bias. The theory has the following components. In countries with poor governance, it is optimal for insiders to own large stakes in corporations and for large shareholders to monitor insiders. Foreign portfolio investors will exhibit a large home bias against such countries because their investment is limited by the shares held by insiders (the "direct effect" of poor governance) and domestic monitoring shareholders ("the indirect effect").> ; Foreigners can also enter as foreign direct investors; if they are from countries with good governance, they have a comparative advantage as insider monitors in countries with poor governance, so that the relative importance of foreign direct investment in total foreign equity investment is negatively related to the quality of governance. Using two datasets, we find strong evidence that the theory can help explain the evolution of the home bias. Using country-level U.S. data, we find that on average the home bias of U.S. investors towards the 46 countries with the largest equity markets did not fall over the past decade, but it decreased the most towards countries in which the ownership by corporate insiders decreased, and the importance of foreign direct investment fell in countries in which ownership by corporate insiders fell. Using firm-level data for Korea, we find evidence of the additional indirect effect of poor governance on portfolio equity investment by foreign investors.Investments, Foreign ; Globalization

Recent Developments in Employment Relations in the Philippines

We seek to describe recent developments in employment relations in the Philippines, placing these developments in the contexts of the distinctive elements of the Philippine social/political/industrial relations systems as well as the ongoing trade-based and functional integration of international markets and the recent regional economic crisis. We find that, while some firms are pursuing functional flexibility and more cooperative employment relations, the logic of competition has primarily induced firms to adopt practices that promote numerical flexibility such that a core-periphery workforce is created. We argue that the labor movement in the Philippines has been hampered in its efforts to effectively counter employer strategies by its low density, its fragmentation, and an unfavorable public policy environment; Philippine labor unions have, however, made some recent gains in organizing and inter-union coordination. We also argue that governments, both national and regional, have not done enough to counteract the negative effects of market integration on workers nor to evolve the Philippines into a higher value-added exporter