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In this paper, we evaluate the consequences of super-active fiscal policy rules - that is, rules that call for tax cuts and/or spending increases as the government's debt level rises - in a standard New Keynesian model subject to an occasionally-binding zero lower bound on the monetary policy interest rate. We show that such seemingly irresponsible, debt-financed fiscal stimulus at the ZLB, unbacked by any promise of future tax increases or spending cuts, not only improves economic stability by acting as an automatic stabilizer, but also, somewhat paradoxically, reduces government debt accumulation. When evaluated using a model-consistent measure of welfare, fiscal rules calibrated to the U.S. response during both the Great Recession and COVID recession, combined with a weak monetary policy response to inflation, outperform a monetary policy that responds strongly to inflation and reduce the frequency of episodes at the ZLB.

I study the welfare performance of a policy regime of fiscal activism in which fiscal policy acts as an automatic stabilizer and controls inflation, while monetary policy pegs the nominal interest rate. When evaluated through the lens of a standard New Keynesian model, accounting for price and wage rigidities and for a zero lower bound (ZLB) on the nominal interest rate, fiscal activism can substantially outperform inflation targeting in the face of both demand shocks and technology shocks. Fiscal activism can also eliminate the occurrence of ZLB episodes.

We analyse the welfare impact of greater wage flexibility in the presence of an occasionally binding zero lower bound (ZLB) constraint on the nominal interest rate.We show that the ZLB constraint generally amplifies the adverse effects of greaterwage flexibility onwelfare when the central bank follows a conventional Taylor rule. When demand shocks are the driving force, the ZLB implies that an increase in wage flexibility reduces welfare even under the optimal monetary policy with commitment. Gal´ı acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through an I+D Grant (ECO2017-87827) and the Severo Ochoa Programme for Centres of Excellence in R&D (SEV-2015-0563).

Anomalies of the brachial plexus including the distribution of the nerves as well as its terminal branches in the upper limb have been largely described in the literature. In this case report we describe a further variant of brachial plexus formation identified during routine anatomical dissection of the right upper limb of a 62-year-old Caucasian female cadaver. On the right side no musculocutaneous nerve was identified, the median nerve was formed as expected but a short extra branch communicating between the lateral cord and the medial head of the median nerve appeared. Coracobrachialis muscle was innervated by a direct branch from the lateral cord, while biceps brachialis and brachialis muscles were reached by collaterals of the median nerve. Moreover, in the distal half of the upper limb, the median nerve contributed to the innervation of the lateral aspect of the forearm skin via the lateral cutaneous nerve of the forearm. In order to analyze this specific variant relevance we compared it with all the similar previous reported cases, trying to explain the embryological bases of the variant. The knowledge of anatomical variations of peripheral nerves is pivotal not only for surgeons, radiologists and anesthesiologists that may operate on the axilla, but also for every medical doctor to understand inexplicable clinical signs.

We analyze the welfare impact of greater wage flexibility while taking into account explicitly the existence of the zero lower bound (ZLB) constraint on the nominal interest rate. We show that the ZLB constraint generally amplifies the adverse effects of greater wage flexibility on welfare when the central bank follows a conventional Taylor rule. When demand shocks are the driving force, the presence of the ZLB implies that an increase in wage flexibility reduces welfare even under the optimal monetary policy with commitment.

We present and discuss a late-nineteenth century clinical case described by Professor Taruffi in a scientific paper titled “Scheletro con prosopoectasia e tredici vertebre dorsali” (Skeleton with prosopoectasia and thirteen thoracic vertebrae). Taruffi could not explain the disproportionate skeletal and visceral growth, and the case could therefore be considered an unrecognized case of acromegaly. The anatomopathological specimens and the wax model cited in the paper are currently hosted at the “Luigi Cattaneo” Anatomical Wax Collection of Bologna University; however, some inaccuracies and uncertainties as to their attribution to the same case have remained to this day. The skeletal remains were examined macroscopically to investigate any structural abnormalities and pathological changes. In addition, thanks to archival, museum inventory and literature research, we documented the systematic relationship between the paper and the samples and were able to ascribe the abnormally dilated dried stomach, currently displayed in a different showcase, to the same case. This is, to our knowledge, the first case of acromegaly in the history of medical literature which also includes a visceral specimen. As far as we know, there are no reports of the occurrence of severe gastromegaly in patients with acromegaly. In view of this rare association and, to date, endocrinological research, we hypothesize a further pathogenic mechanism by which acromegaly could have induced this massive dilatation. Taruffi’s work represents an immensely valuable scientific/artistic heritage and is still cited in contemporary endocrinological literature, demonstrating its relevant contribution to the historical evolution of the disease through the nineteenth and twentieth centuries.

I compare nominal GDP level targeting to flexible inflation targeting in a small New Keynesian model subject to the zero lower bound on nominal policy rates. First, I study the performance of optimal discretionary policies. I find that, for a standard calibration, inflation targeting under discretion leaves the economy open to a deflationary trap. Nominal GDP level targeting under discretion, by contrast, provides a firm nominal anchor to the economy. Second, I study simple policy rules and the role of smoothing in the rules. With smoothing, a Taylor-type rule performs as well as a nominal GDP level rule. These result suggest that inflation targeting should not be ditched. Still, it can be improved significantly, by using policy rate smoothing to anchor inflation firmly.

We study interactions between monetary policy, which sets nominal interest rates, and fiscal policy, which levies distortionary income taxes to finance public goods, in a standard, sticky- price economy with monopolistic competition. Policymakers´inability to commit in advance to future policies gives rise to excessive inflation and excessive public spending, resulting in welfare losses equivalent to several percent of consumption each period. We show how appointing a conservative monetary authority, which dislikes inflation more than society does, can considerably reduce these welfare losse and that optimally the monetary authority is predominatly concerned about inflation. Full conservatism, i.e., exclusive concern about inflation, entirely eliminates the welfare losses from discretionary monetary and fiscal policymaking, provided monetary policy is determined after fiscal policy each period. Full conservatism, however, is severely suboptimal when monetary policy is determined simultaneously with fiscal policy or before fiscal policy each period.

Policymakers often use the output gap, a noisy signal of economic activity, as a guide for setting monetary policy. Noise in the data argues for policy caution. At the same time, the zero bound on nominal interest rates constrains the central bank's ability to stimulate the economy during downturns. In such an environment, greater policy stimulus may be needed to stabilize the economy. Thus, noisy data and the zero bound present policymakers with a dilemma in deciding the appropriate stance for monetary policy. I investigate this dilemma in a small New Keynesian model, and show that policymakers should pay more attention to output gaps than suggested by previous research.

The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway plays a central role in cell growth, proliferation, differentiation, and survival under physiological conditions. Aberrant regulation of the PI3K/Akt/mTOR signal transduction network has been observed in a wide range of neoplasias, including malignant hematological disorders. This observation suggests that this signaling cascade could also play a critical role during normal hematopoiesis, a highly regulated process which results in the formation of all blood lineages. The development of blood cells comprises a complex series of events which are mainly regulated through the actions of cytokines, a large family of extracellular ligands than can stimulate many biological responses in a wide array of cell types. Several of these cytokines are known to activate the PI3K/Akt/mTOR signal transduction network and thus regulate proliferation, survival, and differentiation events during hematopoiesis. Moreover, hematopoiesis is strictly dependent on the correct functions of the bone marrow microenvironment. Here, we review the evidence which links the signals emanating from the PI3K/Akt/mTOR cascade with the functions of hematopoietic stem cells and the process of lineage commitment, which then gives rise to myeloid lineage-restricted cells. We then further highlight the key role played by the PI3K/Akt/mTOR network during erythropoiesis, megakaryocytopoiesis, and granulo-cytopoiesis/monocytopoiesis.

Does an inflation conservative central bank à la Rogoff (1985) remain desirable in a setting with endogenous fiscal policy? To provide an answer we study monetary and fiscal policy games without commitment in a dynamic stochastic sticky price economy with monopolistic distortions. Monetary policy determines nominal interest rates and fiscal policy provides public goods generating private utility. We find that lack of fiscal commitment gives rise to excessive public spending. The optimal inflation rate internalizing this distortion is positive, but lack of monetary commitment robustly generates too much inflation. A conservative monetary authority thus remains desirable. Exclusive focus on inflation by the central bank recoups large part - in some cases all - of the steady state welfare losses associated with lack of monetary and fiscal commitment. An inflation conservative central bank tends to improve also the conduct of stabilization policy.

Ignoring the existence of the zero lower bound on nominal interest rates one considerably understates the value of monetary commitment in New Keynesian models. A stochastic forward-looking model with lower bound, calibrated to the U.S. economy, suggests that low values for the natural rate of interest lead to sizeable output losses and deflation under discretionary monetary policy. The fall in output and deflation are much larger than in the case with policy commitment and do not show up at all if the model abstracts from the existence of the lower bound. The welfare losses of discretionary policy increase even further when inflation is partly determined by lagged inflation in the Phillips curve. These results emerge because private sector expectations and the discretionary policy response to these expectations reinforce each other and cause the lower bound to be reached much earlier than under commitment. JEL Klassifikation: E31, E52

This paper characterizes the optimal inflation buffer consistent with a zero lower bound on nominal interest rates in a New Keynesian sticky-price model. It is shown that a purely forward-looking version of the model that abstracts from inflation inertia would significantly underestimate the inflation buffer. If the central bank follows the prescriptions of a welfare-theoretic objective, a larger buffer appears optimal than would be the case employing a traditional loss function. Taking also into account potential downward nominal rigidities in the price-setting behavior of firms appears not to impose significant further distortions on the economy. JEL Klassifikation: C63, E31, E52 .

We determine optimal monetary policy under commitment in a forwardlooking New Keynesian model when nominal interest rates are bounded below by zero. The lower bound represents an occasionally binding constraint that causes the model and optimal policy to be nonlinear. A calibration to the U.S. economy suggests that policy should reduce nominal interest rates more aggressively than suggested by a model without lower bound. Rational agents anticipate the possibility of reaching the lower bound in the future and this amplifies the effects of adverse shocks well before the bound is reached. While the empirical magnitude of U.S. mark-up shocks seems too small to entail zero nominal interest rates, shocks affecting the natural real interest rate plausibly lead to a binding lower bound. Under optimal policy, however, this occurs quite infrequently and does not imply positive average inflation rates in equilibrium. Interestingly, the presence of binding real rate shocks alters the policy response to (non-binding) mark-up shocks.

A major factor undermining successful cancer treatment is the occurrence of resistance to conventional treatments such as chemotherapy and ionizing radiation. Evidence accumulated over the recent years has indicated the phosphoinositide 3-kinase/Akt signal transduction pathway as one of the major factors implicated in cancer resistance to conventional therapies. Indeed, the phosphoinositide 3-kinase/Akt axis regulates the expression and/or function of many anti-apoptotic proteins which strongly contributes to cancer cell survival. As a result, small molecules designed to specifically target key components of this signaling network are now being developed for clinical use as single therapeutic agents and/or in combination with other forms of therapy to overcome resistance. Initially, the phosphoinositide 3-kinase/Akt signal transduction pathway has been mainly investigated in solid tumors. Recently, however, this network has also been recognized as an important therapeutic target in human leukemias. Specific inhibition of this signalling pathway may be a valid approach to treat these diseases and increase the efficacy of standard types of therapy.

We determine optimal discretionary monetary policy in a New Keynesian model when nominal interest rates are bounded below by zero. Nominal interest rates should be lowered faster in response to adverse shocks than in the case without bound. Such ‘pre-emptive easing’ is optimal because expectations of a possibly binding bound in the future amplify the effects of adverse shocks. Calibrating the model to the US economy we find the easing effect to be quantitatively important. Moreover, the lower bound binds rather frequently and imposes significant welfare losses. Losses increase further when inflation is partly determined by lagged inflation in the Phillips curve. Targeting positive inflation rates reduces the frequency of a binding lower bound, but tends to reduce welfare compared to a target rate of zero. The welfare gains from policy commitment, however, appear significant and are much larger than in the case without lower bound.

We determine optimal monetary policy under commitment in a forwardlooking New Keynesian model when nominal interest rates are bounded below by zero. The lower bound represents an occasionally binding constraint that causes the model and optimal policy to be nonlinear. A calibration to the U.S. economy suggests that policy should reduce nominal interest rates more aggressively than suggested by a model without lower bound. Rational agents anticipate the possibility of reaching the lower bound in the future and this amplifies the effects of adverse shocks well before the bound is reached. While the empirical magnitude of U.S. mark-up shocks seems too small to entail zero nominal interest rates, shocks affecting the natural real interest rate plausibly lead to a binding lower bound. Under optimal policy, however, this occurs quite infrequently and does not require targeting a positive average rate of inflation. Interestingly, the presence of binding real rate shocks alters the policy response to (non-binding) mark-up shocks. JEL Klassifikation: C63, E31, E52 .

We determine optimal monetary policy under commitment in a forwardlooking New Keynesian model when nominal interest rates are bounded below by zero. The lower bound represents an occasionally binding constraint that causes the model and optimal policy to be nonlinear. A calibration to the U.S. economy suggests that policy should reduce nominal interest rates more aggressively than suggested by a model without lower bound. Rational agents anticipate the possibility of reaching the lower bound in the future and this amplifies the effects of adverse shocks well before the bound is reached. While the empirical magnitude of U.S. mark-up shocks seems too small to entail zero nominal interest rates, shocks affecting the natural real interest rate plausibly lead to a binding lower bound. Under optimal policy, however, this occurs quite infrequently and does not require targeting a positive average rate of inflation. Interestingly, the presence of binding real rate shocks alters the policy response to (non-binding) mark-up shocks.