5,934 research outputs found
Human Resources Strategy: The Era of Our Ways
The purpose of this chapter is to discuss some of the main features and trends in human resources (HR) strategy. Inasmuch as people are among the most important resources available to firms, one could argue that HR strategy should be central to any debate about how firms achieve competitive advantage. But this āpeople are our most important assetā argument is actually fairly hollow in light of the evidence. Far too many articles on HR start with this premise, but the reality is that organizations have historically not rested their fortunes on human resources. The HR function remains among the least influential in most organizations, and competitive strategies have not typically been based on the skills, capabilities, and behaviors of employees. In fact, as Snell, Youndt and Wright (1996:62) noted, in the past executives have typically tried to ātake human resources out of the strategy equation--i.e., by substituting capital for labor where possible, and by designing hierarchical organizations that separate those who think from those who actually do the work.
Zinc calixarene complexes for the ring opening polymerization of cyclic esters
Reaction of Zn(CāFā
)āĀ·toluene (two equivalents) with 1,3-dipropoxy-p-tert-butyl-calix[4]arene (LĀ¹Hā) led to the isolation of the complex [{Zn(CāFā
)}āLĀ¹] (1), whilst similar use of Zn(Me)ā resulted in the known complex [{Zn(Me)}āLĀ¹] (2). Treatment of LĀ¹Hā with in situ prepared Zn{N(SiMeā)ā}ā in refluxing toluene led to the isolation of the compound [(Na)ZnN(SiMeā)āLĀ¹] (3). The stepwise reaction of LĀ¹Hā and sodium hydride, followed by ZnClā and finally NaN(SiMeā)ā yielded the compound [Zn{N(SiMeā)ā}āLĀ¹] (4). The reaction between three equivalents of Zn(CāFā
)āĀ·toluene and oxacalix[3]arene (LĀ²Hā) at room temperature formed the compound {[Zn(CāFā
)]āLĀ²} (5); heating of 5 in acetonitrile caused the ring opening of the parent oxacalix[3]arene and rearrangement to afford the complex [(LĀ²)Znā(CāFā
)(R)(RH)OH]Ā·5MeCN R = CāFā
CHā-(p-įµBuPhenolate-CHāOCHāā)āāp-įµBuPhenolate-CHāOā»)Ā³ā» (6). The molecular structures of the new complexes 1, 3 and 6, together with that of the known complex 2, whose solid state structure has not previously been reported, have been determined. Compounds 1, 3ā5 have been screened for the ring opening polymerization (ROP) of Īµ-caprolactone (Īµ-CL) and rac-lactide. Compounds featuring a ZnāCāFā
fragment were found to be poor ROP pre-catalysts as they did not react with benzyl alcohol to form an alkoxide. By contrast, compound 4, which contains a zinc silylamide linkage, was the most active of the zinc-based calix[4]arene compounds screened and was capable of ROP at ambient temperature with 65% conversion over 4 h
The Stock of External Sovereign Debt: Can We Take the Data At āFace Valueā?
The stock of sovereign debt is typically measured at face value. This is a misleading indicator when debts are issued with different contractual forms. In this paper we construct a new measure of the stock of external sovereign debt for 100 developing countries from 1979 to 2006 that is invariant to contractual form, and illustrate five problems with debt stocks measured at face value. First, we show that correcting for differences in the contractual form of debt paints a very different quantitative, and in some cases also qualitative, picture of the stock of developing country external sovereign debt. Second, rankings of indebtedness across countries, which were historically used to define eligibility for debt forgiveness, are sometimes inverted once we correct for differences in contractual form. Third, the empirical performance of the benchmark quantitative model of sovereign debt deteriorates by between 40 to 70 percent once model-consistent measures of debt are used. Fourth, we show how the spread of aggregation clauses in debt contracts which award creditors voting power in proportion to the contractual face value may introduce inefficiencies into the process of restructuring sovereign debts. Fifth, we show how the use of contractual face values gives issuing countries the ability to manipulate their debt stock data, and illustrate the use of these techniques in practice.
Augmented Adaptive Control of a Wind Turbine in the Presence of Structural Modes
Wind turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, potentially causing component fatigue and failure. Two key technology drivers for turbine manufacturers are increasing turbine up time and reducing maintenance costs. Since the trend in wind turbine design is towards larger, more flexible turbines with lower frequency structural modes, manufacturers will want to develop methods to operate in the presence of these modes. Accurate models of the dynamic characteristics of new wind turbines are often not available due to the complexity and expense of the modeling task, making wind turbines ideally suited to adaptive control. In this paper, we develop theory for adaptive control with rejection of disturbances in the presence of modes that inhibit the controller. We use this method to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the interference of certain structural modes in feedback. The control objective is accomplished by collectively pitching the turbine blades. The adaptive pitch controller for Region 3 is compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller
Discovery of a Classic FR-II Broad Absorption Line Quasar from the FIRST Survey
We have discovered a remarkable quasar, FIRST J101614.3+520916, whose optical
spectrum shows unambiguous broad absorption features while its double-lobed
radio morphology and luminosity clearly indicate a classic Fanaroff-Riley Type
II radio source. Its radio luminosity places it at the extreme of the recently
established class of radio-loud broad absorption line quasars (Becker et al.
1997, 2000; Brotherton et al. 1998). Because of its hybrid nature, we speculate
that FIRST J101614.3+520916 is a typical FR-II quasar which has been
rejuvenated as a broad absorption line (BAL) quasar with a Compact Steep
Spectrum core. The direction of the jet axis of FIRST J101614.3+520916 can be
estimated from its radio structure and optical brightness, indicating that we
are viewing the system at a viewing angle of > 40 degrees. The position angles
of the radio jet and optical polarization are not well-aligned, differing by 20
to 30 degrees. When combined with the evidence presented by Becker et al.
(2000) for a sample of 29 BAL quasars showing that at least some BAL quasars
are viewed along the jet axis, the implication is that no preferred viewing
orientation is necessary to observe BAL systems in a quasar's spectrum. This,
and the probable young nature of compact steep spectrum sources, leads
naturally to the alternate hypothesis that BALs are an early stage in the lives
of quasars.Comment: 14 pages, 6 postscript figures; accepted for publication in the
Astrophysical Journa
Local BDNF Delivery to the Injured Cervical Spinal Cord using an Engineered Hydrogel Enhances Diaphragmatic Respiratory Function.
We developed an innovative biomaterial-based approach to repair the critical neural circuitry that controls diaphragm activation by locally delivering brain-derived neurotrophic factor (BDNF) to injured cervical spinal cord. BDNF can be used to restore respiratory function via a number of potential repair mechanisms; however, widespread BDNF biodistribution resulting from delivery methods such as systemic injection or lumbar puncture can lead to inefficient drug delivery and adverse side effects. As a viable alternative, we developed a novel hydrogel-based system loaded with polysaccharide-BDNF particles self-assembled by electrostatic interactions that can be safely implanted in the intrathecal space for achieving local BDNF delivery with controlled dosing and duration. Implantation of BDNF hydrogel after C4/C5 contusion-type spinal cord injury (SCI) in female rats robustly preserved diaphragm function, as assessed b
Biodegradation of high-concentration isopropanol by a solvent-tolerant thermophile, Bacillus pallidus
The aerobic biodegradation of high-concentration,
to 24 g l
ā1
, 2-propanol (IPA) by a thermophilic isolate
ST3, identified as
Bacillus pallidus
, was successfully carried
out for the first time. This solvent-tolerant
B. pallidus
utilized
IPA as the sole carbon source within a minimal salts
medium. Cultivation was carried out in 100-ml shake flasks
at 60Ā°C and compared with cultivation within a 1-l stirred
tank reactor (STR). Specific growth rate () was about
0.2 hā1
for both systems, with a maximum cell density of 2.4 x 10
8 cells mlā1
obtained with STR cultivation. During exponential
growth and stationary phase, IPA biodegradation
rates were found to be 0.14 and 0.02 g l
ā1hā1, respectively, in
shake-flask experiments, whereas corresponding values of
0.09 and 0.018 g l
ā1hā1
were achievable in the STR. Generation
of acetone, the major intermediate in aerobic IPA biodegradation,
was also monitored as an indicator of
microbial IPA utilization. Acetone levels reached a maximum
of 2.2ā2.3 g lā1
after 72 and 58 h for 100-ml and 1-l systems,
respectively. Both IPA and acetone were completely
removed from the medium following 160 and 175 h, respectively,
during STR growth, although this was not demonstrated
within shake-flask reactions. Growth of
B. pallidus
on acetone or IPA alone demonstrated that the maximum
growth rate () obtainable was 0.247 hā1
at 4 g lā1
acetone
and 0.202 hā1
at 8 g lā1
IPA within shake-flask cultivation.
These results indicate the potential of the solvent-tolerant
thermophile
B. pallidus
ST3 in the bioremediation of hot
solvent-containing industrial waste streams
Ruthenium carbamoyl complexes: coordination chemistry and CO release
Reaction of Ru(CO) 4Br 2 with a series of heterocyclic amines leads to a family of ruthenium carbamoyl complexes. These are analogous to the related ferracyclic systems reported by us as potential photoCORM systems (Chem. Commun., 2020, 56, 4300ā4303). In contrast to the iron compounds, the ruthenium carbamoyls release CO only when irradiated in the UV, and show no activity as anti-inflammatory agents
Exposing Undergraduates to Design, Fabrication, and Large-Scale Experimentation in a Structural Steel Design Course
During Fall 2017, Spring and Fall 2018 quarters, various hands-on design, fabrication, and large-scale experimental projects were incorporated into a 10-week undergraduate structural steel design course offered in the Department of Architectural Engineering at California Polytechnic State University ā San Luis Obispo. Through these projects students investigated one or two unique steel lateral force resisting systems (LFRS) consisting of either: special moment frame (SMF), special concentric braced frame (SCBF), and/or buckling restrained braced frame (BRBF). Students completed design calculations per the American Institute of Steel Construction steel building and seismic codes, visualized their final design using AutoCAD software, constructed and tested the LFRS specimen. Finally, students compared test results to predictions determined via code equations.
These new projects offer a novel approach for engaging students in the process of learning steel design where they practice the technical structural design and analysis competencies while refining visual/written/oral communication, project management, construction, experimentation, and data analysis skills. Student feedback collected for each course offering indicated that students had a better visual and physical understanding of various steel LFRS systems by undergoing the complete cycle of design, fabrication, testing, and analysis. As a result, students were able to more fully comprehend consequences of their design decisions, lessons which they will hopefully draw on in their future structural engineering career focusing on seismic design
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