3,148 research outputs found
Technology, organization and materiality: Reflections on the Problem of Agency
In management and information systems research, there has been a long-standing debate over the relationship between technology and the organization in which it is embedded. This debate flares up periodically and this is one such time. At one extreme is technological determinism, which makes the claim that technology is the cause and organizational change is the effect. At the other extreme is social determinism, which claims that social action and interaction is the cause and technological change is the effect. Is there a way out of this debate? How can we make sense of the interactions between people and machines? In this paper, we will examine the debate, discuss what is at stake in its resolution and explore an alternative
Testing the Bayesian confidence hypothesis
Asking subjects to rate their confidence is one of the oldest procedures in psychophysics. Remarkably, quantitative models of confidence ratings have been scarce. The Bayesian confidence hypothesis (BCH) states that an observer’s confidence rating is monotonically related to the posterior probability of their choice. I will report tests of this hypothesis in two visual categorization tasks: one requiring rapid categorization of a single oriented stimulus, the other a deliberative judgment typically made by scientists, namely interpreting scatterplots. We find evidence against the Bayesian confidence hypothesis in both tasks
Regulation of Xenopus oocyte meiosis arrest by G protein βγ subunits
AbstractBackground: Progesterone induces the resumption of meiosis (maturation) in Xenopus oocytes through a nongenomic mechanism involving inhibition of an oocyte adenylyl cyclase and reduction of intracellular cAMP. However, progesterone action in Xenopus oocytes is not blocked by pertussis toxin, and this finding indicates that the inhibition of the oocyte adenylyl cyclase is not mediated by the α subunits of classical Gi-type G proteins.Results: To investigate the possibility that G protein βγ subunits, rather than α subunits, play a key role in regulating oocyte maturation, we have employed two structurally distinct G protein βγ scavengers (Gtα and βARK-CCAAX) to sequester free Gβγ dimers. We demonstrated that the injection of mRNA encoding either of these Gβγ scavengers induced oocyte maturation. The Gβγ scavengers bound an endogenous, membrane-associated Gβ subunit, indistinguishable from Xenopus Gβ1 derived from mRNA injection. The injection of Xenopus Gβ1 mRNA, together with bovine Gγ2 mRNA, elevated oocyte cAMP levels and inhibited progesterone-induced oocyte maturation.Conclusion: An endogenous G protein βγ dimer, likely including Xenopus Gβ1, is responsible for maintaining oocyte meiosis arrest. Resumption of meiosis is induced by Gβγ scavengers in vitro or, naturally, by progesterone via a mechanism that suppresses the release of Gβγ
The nonlinear anomalous lattice elasticity associated with the high-pressure phase transition in spodumene: A high precission static compression study
The high-pressure behavior of the lattice elasticity of spodumene, LiAlSi2O6,
was studied by static compression in a diamond-anvil cell up to 9.3 GPa.
Investigations by means of single-crystal XRD and Raman spectroscopy within the
hydrostatic limits of the pressure medium focus on the pressure ranges around
similar to 3.2 and similar to 7.7 GPa, which have been reported previously to
comprise two independent structural phase transitions. While our measurements
confirm the well-established first-order C2/c-P2(1)/c transformation at 3.19
GPa (with 1.2% volume discontinuity and a hysteresis between 0.02 and 0.06
GPa), both unit-cell dimensions and the spectral changes observed in
high-pressure Raman spectra give no evidence for structural changes related to
a second phase transition. Monoclinic lattice parameters and unit-cell volumes
at in total 59 different pressure points have been used to re-calculate the
lattice-related properties of spontaneous strain, volume strain, and the bulk
moduli as a function of pressure across the transition. A modified Landau free
energy expansion in terms of a one component order parameter has been developed
and tested against these experimentally determined data. The Landau solution
provides a much better reproduction of the observed anomalies than any
equation-of-state fit to data sets truncated below and above P (tr), thus
giving Landau parameters of K (0) = 138.3(2) GPa, K' = 7.46(5), lambda (V) =
33.6(2) GPa, a = 0.486(3), b = -29.4(6) GPa and c = 551(11) GPa
D3.6 Relaying and Cooperative Communications Enhancements Based on Positioning Data (Final Report)
Epiglottis cross-sectional area and oropharyngeal airway length in male and female obstructive sleep apnea patients
INTRODUCTION: Obstructive sleep apnea (OSA) is a male-predominant condition, characterized by repeated upper-airway collapse with continued diaphragmatic efforts during sleep, and is accompanied by severe physiological consequences. Multiple morphological aspects, including epiglottis cross-sectional area (CSA) and oropharyngeal airway length (OPAL), can contribute to airway collapsibility in the condition. This study focused on the effects of OSA severity, sex, and race on OPA dimensions. MATERIALS AND METHODS: Two high-resolution T(1)-weighted image series were collected from 40 mild-to-severe OSA subjects (age 46.9±9 years, body mass index 30.4±5.4 kg/m(2), Apnea–Hypopnea Index score 32.8±22.5, 28 males) and 54 control subjects (47±9 years, 24.7±3.8 kg/m(2), 32 males) using a 3 T magnetic resonance-imaging scanner. Caucasian, Asian, African-American, and “other” subjects constituted the study pool. Both image series were realigned and averaged, and reoriented to a common space. CSA and OPAL were measured, normalized for subject height, and compared between sexes and disease-severity levels in OSA and control subjects. RESULTS: Significantly reduced epiglottis CSA appeared only in severe OSA vs controls (P=0.009). OPAL increased significantly with OSA severity vs controls (mild, P=0.027; moderate, P<0.001; severe, P<0.001). OSA males showed increased CSA and greater OPAL than OSA females, which may underlie the increased proportion of affected males with higher apnea–hypopnea index scores. However, no significant differences appeared between CSA and OPAL measures for male and female controls, suggesting that airway morphology may not be the sole contributor for airway collapse. No ethnic or racial differences appeared for CSA or OPAL measures. CONCLUSION: Sex-based reductions in epiglottis CSA and increased OPAL in OSA subjects may enhance airway-collapse vulnerability, more so with greater disease severity, and partially underlie male vs female susceptibility to the sleep disorder
The Functions of Music-Listening across Cultures: The Development of a Scale Measuring Personal, Social and Cultural Functions of Music
We examined the functions of music-listening from a cross-cultural perspective. Two studies were conducted to capture personal, social and cultural experiences with music. Young people were sampled; mainly online surveys were used. Study 1 is a qualitative multicultural study that identified seven main functions of music: background, memories, diversion, emotion, self-regulation, reflection of self, and social bonding. In study 2, based on the qualitative data, we developed and validated a scale measuring Ratings of Experienced Social, PErsonal and Cultural Themes of MUSIC functions (RESPECT-MUSIC) in three cultural samples (Latin-American, Anglo- Saxon, and Germanic). A ten-factorial solution was found to be structurally equivalent and reliable across three cultural samples. The factors represent the functions: background, dancing, emotions, venting, focus, value development, political attitudes, social bonding with friends, family bonding, and cultural identity. Limitations of this research and future directions are discussed. The investigation complements previous psychological research on music with a cross-cultural perspective
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