Aggregate recruiting intensity

We develop an equilibrium model of firm dynamics with random search in the labor market where hiring firms exert recruiting effort by spending resources to fill vacancies faster. Consistent with microevidence, fast-growing firms invest more in recruiting activities and achieve higher job-filling rates. These hiring decisions of firms aggregate into an index of economywide recruiting intensity. We study how aggregate shocks transmit to recruiting intensity, and whether this channel can account for the dynamics of aggregate matching efficiency during the Great Recession. Productivity and financial shocks lead to sizable pro-cyclical fluctuations in matching efficiency through recruiting effort. Quantitatively, the main mechanism is that firms attain their employment targets by adjusting their recruiting effort in response to movements in labor market slacknes

Aggregate recruiting intensity

We develop a model of firm dynamics with random search in the labor market where hiring firms exert recruiting effort by spending resources to fill vacancies faster. Consistent with micro evidence, in the model fast-growing firms invest more in recruiting activities and achieve higher job-filling rates. In equilibrium, individual decisions of hiring firms aggregate into an index of economy-wide recruiting intensity. We use the model to study how aggregate shocks transmit to recruiting intensity, and whether this channel can account for the dynamics of aggregate matching efficiency around the Great Recession. Productivity and financial shocks lead to sizable pro-cyclical fluctuations in matching efficiency through recruiting effort. Quantitatively, the main mechanism is that firms attain their employment targets by adjusting their recruiting effort as labor market tightness varies. Shifts in sectoral composition can have a sizable impact on aggregate recruiting intensity. Fluctuations in new-firm entry, instead, have a negligible effect despite their contribution to aggregate job and vacancy creations

The photophysical properties of Ruthenium(11) Polypyridyl complexes immobilised in sol-gel matrices

This thesis involves the synthesis and characterisation of sol-gel monoliths doped with Ru(II) polypyridyl complexes. In Chapter 1 an overview of the chemistry of the sol-gel process is given along with an introduction to the photophysical properties of Ru(II) complexes in solution. In the first section of this thesis, the Ru(II) dopants are employed as spectroscopic probes of the sol-gel process, following the reactions as they proceed from the initial sol to the final xerogel. Variations in the photophysical properties of these immobilised complexes were found to accompany changes in the sol-gel microenvironment. As such, these Ru(II) dopants can be employed to yield information on the evolution of the sol-gel reactions. On the one hand, the blue shift in the emission energy of [Ru(bpy)3]2' and [Ru(phen)3]2+ associated with the restrictive nature of the sol-gel matrix as compared to solution, was used to probe the early stages of the sol-gel process. Investigations into a number of parameters (i.e. pH, temperature and water/silane ratio) which effect these reactions were carried out. On the other hand, the photophysical behaviour of the immobilised [Ru(dpp)a]2+ was found to probe the final stages (the drying reactions) of the sol-gel process. This section also investigates the potential application of the acid/base chemistry of a pyridyltriazole complex as a probe of changes in acidity which may occur during the sol-gel process. The final section of this thesis involves using the known information of the sol-gel system to examine the excited state processes of Ru(II) polypyridyl complexes under a novel environment. Chapters 5 and 6 investigate the temperature dependence of the excited-state decay of a range of complexes in solution and in the sol-gel matrix. Significant differences were found depending on the individual complex and also on the nature of the host matrix. These studies suggest that the population of the 3MC state which is responsible for the photodecomposition of these complexes in solution may be inhibited in the solgel matrix and that as such, the photolability of a number of these complexes decreases upon immobilisation

An anatomy of monopsony : Search frictions, amenities and bargaining in concentrated markets

We contribute a theory in which three channels interact to determine the degree of monopsony power and therefore the markdown of a worker’s spot wage relative to her marginal product: (1) heterogeneity in worker-firm-specific preferences (non-wage amenities), (2) firm granularity, and (3) off- and on-the-job search frictions. We use Norwegian data to discipline each channel and then reproduce new reduced-form empirical relationships between market concentration, job flows, wages and wage inequality. In doing so we provide a novel method for clustering occupations into local labor markets. Our main exercise quantifies the contribution of each channel to income inequality and wage markdowns. The average markdown is 21 percent in our baseline estimation. Removing nonwage amenity dispersion narrows them by a third. Giving the next-lowest-ranked competitor a seat at the bargaining table narrows them by half, suggesting that granularity and strategic interactions in the bargaining process is an important source of markdowns. Removing search frictions narrows them by two-thirds. Each counterfactual reduces wage inequality and increases welfare.publishedVersio

Live imaging of alveologenesis in precision-cut lung slices reveals dynamic epithelial cell behaviour

Damage to alveoli, the gas-exchanging region of the lungs, is a component of many chronic and acute lung diseases. In addition, insufficient generation of alveoli results in bronchopulmonary dysplasia, a disease of prematurity. Therefore visualising the process of alveolar development (alveologenesis) is critical for our understanding of lung homeostasis and for the development of treatments to repair and regenerate lung tissue. Using long-term, time-lapse imaging of precision-cut lung slices, we show alveologenesis for the first time. We reveal that during this process, epithelial cells are highly mobile and we identify specific cell behaviours that contribute to alveologenesis: cell clustering, hollowing and cell extension. Using the cytoskeleton inhibitors blebbistatin and cytochalasin D, we showed that cell migration is a key driver of alveologenesis. This study reveals important novel information about lung biology and provides a new system in which to manipulate alveologenesis genetically and pharmacologically

A bioassay system of autologous human endothelial, smooth muscle cells and leucocytes for use in drug discovery, phenotyping and tissue engineering

Purpose: Blood vessels are comprised of endothelial and smooth muscle cells. Obtaining both types of cells from vessels of living donors is not possible without invasive surgery. To address this we have devised a strategy whereby human endothelial and smooth muscle cells derived from blood progenitors from the same donor could be cultured with autologous leucocytes to generate a same donor ‘vessel in a dish’ bioassay. Basic procedures: Autologous sets of blood outgrowth endothelial cells (BOECs), smooth muscle cells (BO-SMCs) and leucocytes were obtained from 4 donors. Cells were treated in mono and cumulative co-culture conditions. The endothelial specific mediator endothelin-1 along with interleukin (IL)-6, IL-8, tumour necrosis factor α, and interferon gamma-induced protein 10 were measured under control culture conditions and after stimulation with cytokines. Main findings: Co-cultures remained viable throughout. The profile of individual mediators released from cells was consistent with what we know of endothelial and smooth muscle cells cultured from blood vessels. Principle conclusions: For the first time, we report a proof of concept study where autologous blood outgrowth ‘vascular’ cells and leucocytes were studied alone and in co-culture. This novel bioassay has utility in vascular biology research, patient phenotyping, drug testing and tissue engineering

Systemic lupus erythematosus induced by anti-tumour necrosis factor alpha therapy: a French national survey

The development of drug-induced lupus remains a matter of concern in patients treated with anti-tumour necrosis factor (TNF) alpha. The incidence of such adverse effects is unknown. We undertook a retrospective national study to analyse such patients. Between June and October 2003, 866 rheumatology and internal medicine practitioners from all French hospital centres prescribing anti-TNF in rheumatic diseases registered on the website of the 'Club Rhumatismes et Inflammation' were contacted by email to obtain the files of patients with TNF-induced systemic lupus erythematosus. Twenty-two cases were collected, revealing two aspects of these manifestations. Ten patients (six patients receiving infliximab, four patients receiving etanercept) only had anti-DNA antibodies and skin manifestations one could classify as 'limited skin lupus' or 'toxidermia' in a context of autoimmunity, whereas 12 patients (nine patients receiving infliximab, three patients receiving etanercept) had more complete drug-induced lupus with systemic manifestations and at least four American Congress of Rheumatology criteria. One patient had central nervous system manifestations. No patients had lupus nephritis. The signs of lupus occurred within a mean of 9 months (range 3–16 months) in patients treated with infliximab and within a mean of 4 months (range 2–5 months) in patients treated with etanercept. In all cases after diagnosis was determined, anti-TNF was stopped and specific treatment introduced in eight patients: two patients received intravenous methylprednisolone, four patients received oral steroids (15–35 mg/day), and two patients received topical steroids. Lupus manifestations abated within a few weeks (median 8 weeks, standard deviation 3–16) in all patients except one with longer-lasting evolution (6 months). At that time, cautious estimations (unpublished data from Schering Plough Inc. and Wyeth Inc.) indicated that about 7700 patients had been exposed to infliximab and 3000 to etanercept for inflammatory arthritides in France. It thus appears that no drug was more implicated than the other in lupus syndromes, whose incidence was 15/7700 = 0.19% with infliximab and 7/3800 = 0.18% with etanercept. Clinicians should be aware that lupus syndromes with systemic manifestations may occur in patients under anti-TNF alpha treatment

The experimental evaluation of a ternary mixture as an alternative to R22 in the vapour compression refrigeration cycle

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN016439 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Beauty on the Walls: Graffiti and Street Art as a Social Movement

This thesis is an observation of contemporary graffiti and street art and how they unfold as a social movement in Dublin. It discusses Marxist theories of aesthetics and popular culture. It uses interviews with graffiti and street artists, activists, writers and teachers along with visual materials and a number of case studies to identify the internal tensions, the drive for doing the work and the meaning it holds for those involved in the movement. I have identified tensions between ideas around beauty and aesthetics, commercial forms of art and I have highlighted the movement as an attempt at direct action and a social platform for communication and self expression at grassroots level

Cosmopolitan republics and itinerant patriots: The Gulf of Mexico in the Age of Revolutions (1780s–1830s)

This study traces multinational and multiracial revolutionary movements in the Gulf of Mexico, and recovers the lives of dozens of heretofore little known individuals, Afro-Antillean merchants, French corsairs, Spanish philosophers, Italian soldiers, and U.S. privateers who participated in them. These itinerant patriots tried to carve out independent states from former Spanish colonies. They took possession of various regions, issued declarations of independence and constitutions, and promoted immigration. In short, they were state-entrepreneurs. The political propositions that justified these men\u27s efforts to spread revolution around the region shed light on the mechanisms through which states legitimized their political and territorial boundaries in an unstable Atlantic interstate system. Itinerant patriots tried to carve out their own independent states out of former Spanish colonies. Instead of a tale of domination in which a handful of Anglo-Americans conquered an enormous territory in the Gulf South or a tale of celebration in which Spanish-American patriots succeeded in ousting the Spanish crown, this study unearths a far richer story of cross-cultural alliances in the Gulf region, with various sides struggling to define ideas of liberty and belonging. Although these cosmopolitan republics fell into oblivion and gave way to stricter national boundaries by the mid-nineteenth century, for a time they represented political and cultural alternatives to more rigidly exclusive national communities. These itinerant patriots thought of themselves as members of a single republican community, regardless of their place of birth or residence. In a period animated by controversies over borders and loyalties, these individuals shared a bond that was not connected to a particular land. Instead, their liberation expeditions fuelled the globalization of revolutionary values such as popular sovereignty, constitutionalism, natural rights, civil and political freedoms, and self-determination. These men not only positioned themselves as part of a universal fraternity, but also placed themselves at the forefront of a struggle for universal rights in the Atlantic world