6,847 research outputs found
A systems theory perspective on the front-line manager role
The role of agency and the dynamics of systems are critical to understanding how people are managed. Ironically, while this is well understood in practice (e.g. Buckingham & Coffman, 1999) such understanding has not made a sufficient impact in HRM research. This chapter explores the critical role and agency of front-line managers through a systems lens. In so doing we note the limitations of existing understanding which tends to treat gaps between intended and experienced HRM as something to be avoided and mitigated versus acknowledged and embraced. By contrast, the classic lens of systems theory provides a rich intellectual heritage which captures the dynamics of front-line manager agency as grounded by contextually oriented concepts including emergence, informality, self-organizing and entropy. The latter half of the chapter animates these principles in action using the example of the front-line manager role in performance management. The chapter concludes by highlighting how the dynamics of system theory can help advance understanding of front-line manager roles, including that which treats informal practice and deviance from established rules as a practical reality versus a detrimental fault-line in HRM implementation
Discovery of a close substellar companion to the hot subdwarf star HD 149382 - The decisive influence of substellar objects on late stellar evolution
Substellar objects, like planets and brown dwarfs orbiting stars, are
by-products of the star formation process. The evolution of their host stars
may have an enourmous impact on these small companions. Vice versa a planet
might also influence stellar evolution as has recently been argued.
Here we report the discovery of a 8-23 Jupiter-mass substellar object
orbiting the hot subdwarf HD 149382 in 2.391 days at a distance of only about
five solar radii. Obviously the companion must have survived engulfment in the
red-giant envelope. Moreover, the substellar companion has triggered envelope
ejection and enabled the sdB star to form. Hot subdwarf stars have been
identified as the sources of the unexpected ultravoilet emission in elliptical
galaxies, but the formation of these stars is not fully understood. Being the
brightest star of its class, HD 149382 offers the best conditions to detect the
substellar companion. Hence, undisclosed substellar companions offer a natural
solution for the long-standing formation problem of apparently single hot
subdwarf stars. Planets and brown dwarfs may therefore alter the evolution of
old stellar populations and may also significantly affect the UV-emission of
elliptical galaxies.Comment: 17 pages, 2 figures, ApJL accepte
Step by Step to Fairness: Attributing Societal Bias in Task-oriented Dialogue Systems
Recent works have shown considerable improvements in task-oriented dialogue
(TOD) systems by utilizing pretrained large language models (LLMs) in an
end-to-end manner. However, the biased behavior of each component in a TOD
system and the error propagation issue in the end-to-end framework can lead to
seriously biased TOD responses. Existing works of fairness only focus on the
total bias of a system. In this paper, we propose a diagnosis method to
attribute bias to each component of a TOD system. With the proposed attribution
method, we can gain a deeper understanding of the sources of bias.
Additionally, researchers can mitigate biased model behavior at a more granular
level. We conduct experiments to attribute the TOD system's bias toward three
demographic axes: gender, age, and race. Experimental results show that the
bias of a TOD system usually comes from the response generation model
Spin Precession and Time-Reversal Symmetry Breaking in Quantum Transport of Electrons Through Mesoscopic Rings
We consider the motion of electrons through a mesoscopic ring in the presence
of spin-orbit interaction, Zeeman coupling, and magnetic flux. The coupling
between the spin and the orbital degrees of freedom results in the geometric
and the dynamical phases associated with a cyclic evolution of spin state.
Using a non-adiabatic Aharonov-Anandan phase approach, we obtain the exact
solution of the system and identify the geometric and the dynamical phases for
the energy eigenstates. Spin precession of electrons encircling the ring can
lead to various interference phenomena such as oscillating persistent current
and conductance. We investigate the transport properties of the ring connected
to current leads to explore the roles of the time-reversal symmetry and its
breaking therein with the spin degree of freedom being fully taken into
account. We derive an exact expression for the transmission probability through
the ring. We point out that the time-reversal symmetry breaking due to Zeeman
coupling can totally invalidate the picture that spin precession results in
effective, spin-dependent Aharonov-Bohm flux for interfering electrons.
Actually, such a picture is only valid in the Aharonov-Casher effect induced by
spin-orbit interaction only. Unfortunately, this point has not been realized in
prior works on the transmission probability in the presence of both SO
interaction and Zeeman coupling. We carry out numerical computation to
illustrate the joint effects of spin-orbit interaction, Zeeman coupling and
magnetic flux. By examining the resonant tunneling of electrons in the weak
coupling limit, we establish a connection between the observable time-reversal
symmetry breaking effects manifested by the persistent current and by the
transmission probability. For a ring formed by two-dimensional electron gas, weComment: 20 pages, 5 figure
Mitochondrial GTP metabolism controls reproductive aging in C. elegans
Healthy mitochondria are critical for reproduction. During aging, both reproductive fitness and mitochondrial homeostasis decline. Mitochondrial metabolism and dynamics are key factors in supporting mitochondrial homeostasis. However, how they are coupled to control reproductive health remains unclear. We report that mitochondrial GTP (mtGTP) metabolism acts through mitochondrial dynamics factors to regulate reproductive aging. We discovered that germline-only inactivation of GTP-but not ATP-specific succinyl-CoA synthetase (SCS) promotes reproductive longevity in Caenorhabditis elegans. We further identified an age-associated increase in mitochondrial clustering surrounding oocyte nuclei, which is attenuated by GTP-specific SCS inactivation. Germline-only induction of mitochondrial fission factors sufficiently promotes mitochondrial dispersion and reproductive longevity. Moreover, we discovered that bacterial inputs affect mtGTP levels and dynamics factors to modulate reproductive aging. These results demonstrate the significance of mtGTP metabolism in regulating oocyte mitochondrial homeostasis and reproductive longevity and identify mitochondrial fission induction as an effective strategy to improve reproductive health
Antitumor Agents. 266. Design, Synthesis, and Biological Evaluation of Novel 2-(Furan-2-yl)naphthalen-1-ol Derivatives as Potent and Selective Antibreast Cancer Agents
In a continuing study, we explored how the individual rings in neo-tanshinlactone (1) influence its potent and selective in vitro anti-breast cancer activity. Accordingly, we discovered a novel class of anti-breast cancer agents, 2-(furan-2-yl) naphthalen-1-ol derivatives, based on an active C-ring opened model compound 5. Further optimization led to 18 and 21, which showed decreased cytotoxic potency, but better selectivity than neo-tanshinlactone analog 2. Interestingly, compound 20 showed broad cytotoxicity against human cancer cell lines
New betulinic acid derivatives as potent proteasome inhibitors
In this study, 22 new betulinic acid (BA) derivatives were synthesized and tested for their inhibition of the chymotrypsin-like activity of 20S proteasome. From the SAR study, we concluded that the C-3 and C-30 positions are the pharmacophores for increasing the proteasome inhibition effects, and larger lipophilic or aromatic side chains are favored at these positions. Among the BA derivatives tested, compounds 13, 20, and 21 showed the best proteasome inhibition activity with IC50 values of 1.42, 1.56, and 1.80 µM, respectively, which are three- to four-fold more potent than the proteasome inhibition controls LLM-F and lactacystin
Novel curcumin analogs to overcome EGFR–TKI lung adenocarcinoma drug resistance and reduce EGFR–TKI-induced GI adverse effects
Curcumin () down-regulates the expression as well as phosphorylation of epidermal growth factor receptor (EGFR) in lung adenocarcinoma cells expressing gefitinib-resistant EGFR. Thirty-seven newly synthesized curcumin analogues including dimethoxycurcumin (, DMC) were evaluated for their effects on EGFR expression as well as phosphorylation in two gefitinib-resistant lung adenocarcinoma cell lines, CL1-5 (EGFR) and H1975 (EGFR). Based on the identified structure–activity relationships, methoxy substitution at C-3′, C-4′, or both positions favored inhibitory activity (compounds , , , –, , ), while compounds with more polar substituents were generally less active in both cell lines. Compound with a fluorine substituent at C-6′ and its protonated counterpart did not lose activity, suggesting halogen tolerance. In addition, a conjugated linker was essential for activity. Among all evaluated curcumin derivatives, compound showed the best inhibitory effects on both wild-type and mutant EGFR by efficiently inducing gefitinib-insensitive EGFR degradation. Compound also reduced gefitinib-induced gastrointestinal damage in the non-transformed intestinal epithelial cell line IEC-18
Investigation of altered retinal microvasculature in female patients with rheumatoid arthritis: optical coherence tomography angiography detection
Background: Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder that primarily causes symmetrical polyarthritis and bone deformity. In RA patients, sight-threatening inflammatory eye complications would be expected.
Objective: The objective of the study is to ascertain the macular retinal vessel density changes in RA patients and controls using optical coherence tomography angiography (OCTA), and to investigate the association between disease and microvascular density alterations.
Methods: A total of 12 RA patients (24 eyes) and 12 age- and gender-matched control participants (24 eyes) were recruited to the study. We used the Early Treatment Diabetic Retinopathy Study partitioning, hemispheric quadrants and annular partitioning to segment each image into different subregions. The vascular density of superficial retina layer, deep retina layer and conjunctival capillary plexus was quantitatively measured by OCTA and compared with the control group. Correlation analysis was used to explore the relationship between STMI and conjunctival capillaries densities.
Results: In the superficial retinal layer, the vascular density of S, I, L, SL, SR, IL and C1-C5 were significantly decreased in the RA group compared with the control group (P<0.05). For the deep retinal layer, the vascular density of S, SL, SR, IL, C1, C2 and C4 also decreased in RA group. A significant positive correlation was indicated between conjunctival vascular and STMI densities (r = 0.713, P<0.05).
Conclusion: OCTA results suggest that RA patients present with a reduced macular retinal vascular density. These subtle alterations of ocular microcirculation may precede severe eye involvements and may be a potential biomarker for early distinguishing abnormal eyes from healthy eyes
Estimating Mass of Sigma-Meson and Study on Application of the Linear Sigma-Model
Whether the () exists as a real particle is a
long-standing problem in both particle physics and nuclear physics. In this
work, we analyze the deuteron binding energy in the linear model and
by fitting the data, we are able to determine the range of and
also investigate applicability of the linear model for the interaction
between hadrons in the energy region of MeV's. Our result shows that the best
fit to the data of the deuteron binding energy and other experimental data
about deuteron advocates a narrow range for the meson mass as MeV and the concrete values depend on the input parameters
such as the couplings. Inversely fitting the experimental data, our results set
constraints on the couplings. The other relevant phenomenological parameters in
the model are simultaneously obtained.Comment: 12 page
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