To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Collective bargaining in the public sector is under attack. Since 2011, numerous states have eliminated or severely curtailed public employee collective bargaining. For example, Oklahoma repealed its statute that provided collective bargaining rights for employees of mid-sized cities. Tennessee repealed a statute that for more than three decades had provided collective bargaining rights for teachers. The most visible development was Wisconsin’s enactment which, among other things, prohibited bargaining on all subjects except for increases in base wages which were capped at the increase in the Consumer Price Index, prohibited dues checkoff, and required that exclusive bargaining representatives undergo annual elections and receive the votes of at least 51 percent of all employees in the bargaining unit to remain certified. In 2017, Iowa followed Wisconsin’s model, prohibiting dues check-off, requiring annual recertification elections, and making base wages the only mandatory subject of bargaining, but not prohibiting bargaining on other subjects.
The role of panendoscopy in the modern investigation of head and neck cancer is changing with the development of improved radiological techniques, in-office biopsy capabilities and the low rate of synchronous primary tumours. This study aimed to review the indications for panendoscopy in the investigation of newly diagnosed head and neck cancer.
A retrospective review was conducted of 186 patients with newly diagnosed head and neck cancer, between January 2014 and December 2015, at two tertiary centres.
Obtaining a tissue diagnosis was the most common indication for panendoscopy (65 per cent), followed by surgical planning including transoral robotic surgery suitability assessment (22.6 per cent), and the investigation of carcinoma of an unknown primary (11.3 per cent). Two synchronous primary tumours were identified, generating a yield of 1.1 per cent.
Panendoscopy remains integral in the assessment of transoral robotic surgery suitability. Refining indications for modern panendoscopy could reduce the need for this procedure in this cohort of patients.
Macroscopically this sherd appears to be of a fine sandy ware, with ripple burnish. In thin section it can be seen to be a ferruginous clay with a large number of lumps of colloidal iron. It containes a high proportion of small grained and proportionately rounded quartz particles, and a small number of large, calcined flint particles. From the ID, T10, L2,
Extragalactic HII regions and their ionizing star clusters are the most prominent signposts of recent starbirth activity in galaxies. In this paper, we present optical measurements of nearby extragalactic HII regions with the aim of investigating possible relationships between the newborn ionizing clusters and their dynamical environment. Evidence for variations in the measured HII region properties (size, Hα luminosity, and Hα equivalent width) are presented as a function of galaxy type and of position within individual galaxies. These variations, in turn, are compared with the corresponding kinematic and dynamical variations. The apparent sensitivity of the ionizing activity to the dynamical environment suggests that the total masses and upper stellar mass limits of the ionizing clusters are somehow constrained by the ambient tidal stresses and shear flows within the galaxies. We speculate that regions of high tidal stress and kinematic shearing tend to suppress the formation and maintenance of giant molecular clouds, thereby hindering the creation of giant clusters and massive stars therein.
We present a photometric study of the stars in ionizing star clusters embedded in several giant H II regions of M33 (CC93, IC 142, NGC 595, MA2, NGC 604 and NGC 588). Our photometry is based on the HST-WFPC2 images of these clusters. Color-magnitude diagrams and color-color diagrams of these clusters are obtained and are used for estimating the reddenings and ages of the clusters. The luminosity functions (LFs) and initial mass functions (IMFs) of the massive stars in these clusters are also derived. The slopes of the IMFs range from Γ = −0.5 to −2.1. Interestingly, it is found that the IMFs get steeper with increasing galactocentric distance and with decreasing [O/H] abundance.
Background: Perinatal stroke is the most common cause of hemiparetic cerebral palsy. Post-stroke plasticity is well studied in adults, but mechanisms in children are poorly understood. To better understand the relationship between functional connectivity and disability, we used rsfMRI to compare connectivity with sensorimotor dysfunction. Methods: Subjects with periventricular venous infarction were compared to controls. Resting-state BOLD signal was acquired on 3T MRI and analyzed using SPM12. Functional connectivity was computed between S1 and M1 of the left/non-lesioned and right/ lesioned hemisphere. Primary outcome was connectivity expressed as a Pearson correlation coefficient. Motor function was measured using the Assisting Hand Assessment (AHA), and Melbourne Assessment (MA). Proprioceptive function was measured using a robotic position matching task (VarXY). Results: Subjects included 17 PVI and 21 controls. AHA and MA in patients were negatively correlated with connectivity (increased connectivity=poorer performance). Correlations between AHA and connectivity between non-lesioned M1 to bilateral S1s were significant. VarXY in PVI was inversely correlated with connectivity (increased connectivity=improved performance), significantly between non-lesioned S1 and bilateral M1s. Control VarXY was positively correlated with connectivity between non-dominant S1 to bilateral M1s. Conclusions: We demonstrated significant correlations between connectivity and motor/sensory function in PVI patients. Greater insight into understanding reorganization of brain networks following perinatal stroke may facilitate personalized rehabilitation.
Humans are continually diverging and converging with respect to each other. Research across many domains suggests that differentiation and integration are aspects of a more complex set of dynamics, and are not step-wise but interdependent and continuous. Research on conformity in particular reveals that divergence and dissent are forms of cooperation, reflecting concerns for both individual and group integrity.
Spatial studies of the emission line regions in planetary nebulae (PN) can provide insight into the physical and chemical environments across the nebulae. In a collaborative effort by the coauthors, a K-band Fabry-Perot etalon has been coupled with an advanced 256 × 256 InSb focal plane array at the Wyoming Infrared Observatory 2.3m telescope. This system permits us to obtain spatially resolved, 0.24″/pixel, moderate spectral resolution (R ≈ 800), flux-density IR emission line images of astronomical sources. We obtained continuum-subtracted images of Br γ, HeI 2.06 μm, the 2-μm UIR features, and the 3.3 μm PAH dust feature in the PN NGC 6572, NGC 7027, and NGC 7662. One objective was to determine the spatial morphology of two unidentified emission lines, UIR1−2.199 μm, and UIR2−2.287 μm (Geballe et al. 1991). These UIR lines appear in the spectra of many PN (Hora et al. 1997) and in the Orion Nebula (Luhman & Rieke 1996). Geballe et al. suggested that the UIR lines are most likely forbidden transitions and showed that the parent ion ionization potential is ≈ 30–40 eV, while the ionization potential for the ions themselves is 40–60 eV. Here we directly compare the distribution of the UIR emitters to that of the gas (H+,He+) and dust (PAHs).
The present Report covers the period 1982-1984. As with previous Reports, it has not been possible to cover all publications or even every field of research. Some subsections of this Report, the Magellanic Clouds for example, report a body of work as extensive as that in some commissions.
The authors of the earlier version of this book succeeded in accomplishing the goals stated in their preface. Since it was written, Dynamics: Theory and Applications has served as a textbook for teaching graduate students a method of formulating dynamical equations of motion for mechanical systems. The method has proved especially useful for dealing with the complex multibody mechanical systems that in the twentieth and twenty-first centuries have challenged engineers in industry, government, and universities: the Galileo spacecraft sent to Jupiter, the International Space Station, and the robotic manipulator arms aiding astronauts on the Space Shuttle and International Space Station are but a few examples. Kane's method is systematic and easily taught, in a way that enables the student to be conversant with colleagues trained to apply traditional approaches found in the classical literature.
Although the fundamental aspects of the method have not changed during the past three decades, advances and refinements have been made in a number of areas. In certain cases the newer developments facilitate exposition of the topic at hand and lend themselves well to integration with material in the original textbook. The primary purpose of this text, then, is to make the benefits of this progress available for current courses in dynamics.
The preface to the earlier version (which immediately follows this Preface) includes a discussion of the organization of the original book and supporting rationale. Here, we give an overview of the modest alterations made to the earlier structure.
The initial chapter now begins with three brief sections that put the student into position to give a mathematical description of the orientation of a rigid body with respect to a reference frame, when the rigid body has been subjected to successive rotations. Inclusion of these sections provides a formal presentation of topics that typically were covered in classroom discussion. The final section of the first chapter is concerned with differentiation of a scalar function of vectors, which subsequently comes into play in Chapter 6. The original second chapter is divided in two; Chapter 2 deals solely with kinematics, and Chapter 3 is devoted to constraints. The separation focuses attention on the subject of constraints, where there are important distinctions to be made between Kane's method and the classical approaches.
The discipline of dynamics deals with changes of various kinds, such as changes in the position of a particle in a reference frame and changes in the configuration of a mechanical system. To characterize the manner in which some of these changes take place, one employs the differential calculus of vectors, a subject that can be regarded as an extension of material usually taught under the heading of the differential calculus of scalar functions. The extension consists primarily of provisions made to accommodate the fact that reference frames play a central role in connection with many of the vectors of interest in dynamics. A reference frame can be regarded as a massless rigid body, and a rigid body can serve as a reference frame. (A reference frame should not be confused with a coordinate system. Many coordinate systems can be embedded in a given reference frame.) The importance of reference frames in connection with change in a vector can be illustrated by considering the following example. Let A and B be reference frames moving relative to each other, but having one point O in common at all times, and let P be a point fixed in A, distinct from O and thus moving in B. Then the velocity of P in A is equal to zero, whereas the velocity of P in B differs from zero. Now, each of these velocities is a time derivative of the same vector, rOP, the position vector from O to P. Hence, it is meaningless to speak simply of the time derivative of rOP. Clearly, therefore, the calculus used to differentiate vectors must permit one to distinguish between differentiation with respect to a scalar variable in a reference frame A and differentiation with respect to the same variable in a reference frame B.
When working with elementary principles of dynamics, such as Newton's second law or the angular momentum principle, one needs only the ordinary differential calculus of vectors, that is, a theory involving differentiations of vectors with respect to a single scalar variable, generally the time. Consideration of advanced principles of dynamics, such as those presented in later chapters of this book, necessitates, in addition, partial differentiation of vectors with respect to several scalar variables, such as generalized coordinates and motion variables.