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We study the effects of a reform to VAT rules (the reverse charge mechanism on domestic transactions) aimed at eliminating VAT fraud involving cross-border transactions within the European Union (EU). The EU VAT system is prone to fraud involving cross-border transactions between member states, whereby traders either collect VAT without rightfully remitting it to tax authorities or claim a VAT refund to which they are not entitled. We find that pre-reform fraud amounts to around 4% of the trade volume of treated products, or 0.1–0.2% of overall VAT revenues in reform countries in the year leading to the reform. We also show that fraud is concentrated in countries with higher corruption, lower customs efficiency, and lower GDP per capita. Our results represent a lower bound for the gains from local fraud removal, which appears similar in magnitude to the costs incurred by firms to comply with the reform.

In order to stop Value-Added Tax (VAT) fraud, EU member states use the so-called reverse-charge (RC) mechanism, which effectively removes VAT withholding and refunding in business-to-business transactions. Using the German VAT return data, we examine the effects of the introduction of RC and find that requests of input tax refunding decline sharply in the affected industries, supporting the presence of fraud prior to the introduction of RC. Based on our estimates, we quantify the revenue losses from VAT fraud prior to RC implementation in these industries to be around 5% of VAT revenues.

This dissertation is of a cumulative nature and it collects chapters covering distinct topics within the realm of empirical public economics. Each chapter is self-contained, but the topics covered can be divided in two main areas.The first area and the corresponding chapter relate to the literature on charitable giving, focusing on the supply of voluntary work. Specifically, chapter 1 asks whether an increase in community needs, as measured by the presence of refugees at the local level, affects the decision of a person to volunteer. One of the aims of chapter 1 is to empirically investigate the role of “pure altruism” (Andreoni 1989, 1990) as a determinant of the decision to volunteer.The second area includes two chapters that relate to the growing literature on the value-added tax (VAT). In particular, the two chapters investigate the effects of the introduction of reverse charge on VAT reporting. In a nutshell, reverse charge is a tax reform that affects VAT remittance by shifting the VAT remittance liability from the seller to the buyer in business-to-business transactions. While reverse charge is widely applied in the European Union and beyond, evidence on the effects of this reform on VAT systems is scant. Chapter 2 (co-authored with Thiess Büttner.) exploits the introduction of reverse charge in Germany to estimate the volume of VAT fraud that was ongoing prior to the reform. Chapter 3 investigates the effect of the introduction of reverse charge on VAT compliance at the business-to-consumer stage. The following paragraphs provide an abstract of each chapter, while more extensive summaries are provided in the Preface.Chapter 1studies the relationship between changes in community needs and the supply of voluntary work. I present basic theoretical considerations, which suggest that the relationship between voluntary work and an increase in community needs is ambiguous. Then, I test the relationship empirically by proxying community needs with the number of needy people, i.e., refugees, in a county, and by exploiting the quasi-experiment of refugees’ allocation within Germany. I find that doubling the number of refugees increases the probability of volunteering by about 2 percentage points. These estimates imply that 1.45 million people additionally volunteered during the refugee crisis, i.e., more than one person per refugee.Chapter 2focuses on the introduction of the so-called reverse-charge (RC) mechanism. In order to stop Value-Added Tax (VAT) fraud, EU member states use RC, which effectively removes VAT withholding and refunding in business-to-business transactions. Using the German VAT return data, we examine the effects of the introduction of RC and find that requests of input tax refunding decline sharply in the affected industries, supporting the presence of fraud prior to the introduction of RC. Based on our estimates, we quantify the revenue losses from VAT fraud prior to RC implementation in these industries to be around 5% of VAT revenues.Chapter 3explores the effects of the implementation of reverse charge on VAT remittances at the retail stage, using data on individual firms’ tax files from the universe of German VAT returns. The key feature of reverse charge is that VAT remittance liability is shifted from the seller to the buyer, in business-to-business transactions. The shift in remittance liability implies the elimination of multi-stage VAT collection and the concentration of VAT remittance at the retail stage. While an effective tool in the fight against cross-border VAT fraud, reverse charge may thus lead to greater VAT evasion at the retail stage. After identifying retailers affected by the reform, I examine if the introduction of reverse charge reduces their VAT compliance. The findings do not indicate that reverse charge leads to greater evasion at the retail stage.

The analysis of ground-penetrating radar data generally relies on the visual identification of structures on selected profiles and their interpretation in terms of buried features. In simple cases, inverse modelling of the acquired data set can facilitate interpretation and reduce subjectivity. These methods suffer from severe restrictions due to antenna resolution limits, which prevent the identification of tiny structures, particularly in forensic, stratigraphic, and engineering applications. Here, we describe a technique to obtain a high-resolution characterization of the underground, based on the forward modelling of individual traces (A-scans) of selected radar profiles. The model traces are built by superposition of Ricker wavelets with different polarities, amplitudes, and arrival times and are used to create reflectivity diagrams that plot reflection amplitudes and polarities versus depth. A thin bed is defined as a layer of higher or lower permittivity relative to the surrounding material, such that the top and bottom reflections are subject to constructive interference, determining the formation of an anomalous peak in the trace (tuning effect). The proposed method allows the detection of ultra-thin layers, well beyond the Rayleigh vertical resolution of GPR antennas. This approach requires a preliminary estimation of the instrumental uncertainty of common monostatic antennas and takes into account the frequency-dependent attenuation, which causes a spectral shift of the dominant frequency acquired by the receiver antenna. Such a quantitative approach to analyzing radar data can be used in several applications, notably in stratigraphic, forensic, paleontological, civil engineering, heritage protection, and soil stratigraphy applications.

Epilepsy surgery is an option for people with focal onset drug-resistant (DR) seizures but a delayed or incorrect diagnosis of epileptogenic zone (EZ) location limits its efficacy. Seizure semiological manifestations and their chronological appearance contain valuable information on the putative EZ location but their interpretation relies on extensive experience. The aim of our work is to support the localization of EZ in DR patients automatically analyzing the semiological description of seizures contained in video-EEG reports. Our sample is composed of 536 descriptions of seizures extracted from Electronic Medical Records of 122 patients. We devised numerical representations of anamnestic records and seizures descriptions, exploiting Natural Language Processing (NLP) techniques, and used them to feed Machine Learning (ML) models. We performed three binary classification tasks: localizing the EZ in the right or left hemisphere, temporal or extra-temporal, and frontal or posterior regions. Our computational pipeline reached performances above 70% in all tasks. These results show that NLP-based numerical representation combined with ML-based classification models may help in localizing the origin of the seizures relying only on seizures-related semiological text data alone. Accurate early recognition of EZ could enable a more appropriate patient management and a faster access to epilepsy surgery to potential candidates.

We present a technique for the detection of vertebrate skeletons buried at shallow depths through the use of a ground-penetrating radar (GPR). The technique is based on the acquisition of high-resolution data by medium-to-high frequency GPR antennas and the analysis of the radar profiles by a new forward modelling method that is applied on a set of representative traces. This approach allows us to obtain synthetic traces that can be used to build detailed reflectivity diagrams that plot spikes with a distinct amplitude and polarity for each reflector in the ground. The method was tested in a controlled experiment performed at the top of Cerro Los Quesos, one of the most fossiliferous localities in the Ica Desert of Peru. We acquired GPR data at the location of a partially buried fossil skeleton of a large whale and analyzed the reflections associated with the bones using the new technique, determining the possible signature of vertebrae, ribs, the cranium (including the rostrum), and mandibles. Our results show that the technique is effective in the mapping of buried structures, particularly in the detection of tiny features, even below the classical (Ricker and Rayleigh) estimates of the vertical resolution of the antenna in civil engineering and forensic applications.

Hemophagocytic lymphohistiocytosis (HLH) is a hyper-inflammatory syndrome characterized by deficient NK-cell activity, cytokine storm and altered T-cell immunity, potentially sustained by multiple triggers. Recently, a hyperinflammatory condition resembling HLH has emerged as a potential complication of CAR T-cells. HLH represents a diagnostic conundrum due to its rarity, non-specific presentation and lack of validated biomarkers. We investigated a panel of serum cytokines which represent candidate markers to diagnose HLH after CAR-T. We analyzed 2 patients affected by B-cell lymphomas who received anti-CD19 CAR-T and developed HLH defined according to multiple diagnostic criteria. We identified four controls who did not develop HLH: one with CRS without cytopenia, one with cytopenia with CRS, one with both and one with none. We selected a set of acute-phase molecules including CD163, IL33R (quantitated through ELISA), CTLA-4, and CD80 (quantitated through Luminex) and studied their trend in frozen sera collected at parallel time-points. We studied case sera and compared them with controls. All patients developing CRS showed an early peak in IL2R, CD80, CTLA-4 and IL33R, followed by a second, more marked increase in case of HLH, absent in controls. The kinetics of the selected markers suggests that timing and extent of changes might help discriminating HLH from other causes of fever or cytopenia. Serum CD163, CTLA-4, CD80 and IL33R deserve prospective assessment as promising biomarkers to assist in the differential diagnosis between CRS, HLH and non-inflammatory cytopenias after CAR-T.

Objectives: Despite continuous advances in diagnosis, such as the “Two week wait” policy for hospital specialist referral and fast-track diagnostic pathways, lung cancers are detected mostly at advanced stages. Our aim was to evaluate the fast-track diagnostic pathway in a tertiary hospital. Methods: Between March and September 2022, 114 consecutive patients with respiratory symptoms or radiology suspicions of lung cancer were referred to our “Pulmonary Point” outpatient clinic. The time intervals to take in the charges and conduct biopsy and 18FDGPET-CT were prospectively collected. Furthermore, the patients’ experiences were evaluated by means of a six-item questionnaire investigating the outpatient clinic environment and accessibility, the kindness and professional approach of the healthcare professionals, the psychological support provided and an overall evaluation. The data were compared with those of 79 patients observed in the Thoracic Surgery Ambulatory in the pre-COVID-19 pandemic period of March–September 2019 before the fast-track diagnostic pathway for lung cancer was established. Results: The patients were referred to the “Pulmonary Point” outpatient clinic by a General Practitioner in 44 cases (38.5%), by other Specialists in 56 (49.1%) and by an Emergency Department in 14 (12.2%). Among the 114 patients, 104 (91.2%) were visited within 3 working days. Biopsies (FNAB, EBUS, bronchoscopy or surgical) were performed at a median period of 18 days (IQR: 9–26), and 18FDGPET-CT was carried out at a median period of 16 days (IQR: 7–25). The patients referred to the Thoracic Surgery Ambulatory in the period of March–September 2019 were characterized by longer times to biopsy [26 days (IQR: 12–54), p < 0.001] and to 18FDGPET-CT [25 days (IQR: 15–38), p = 0.003]. The patients referred in 2022 reported higher scores in the clinic environment (p < 0.001), psychological support provided (p < 0.001) and overall evaluation (p = 0.02) domains of the questionnaire. Conclusions: The establishment of a dedicated diagnostic pathway improves time to diagnosis and patients’ satisfaction.

Purpose Pulmonary hamartoma is the most common benign tumor of the lung. We analyzed a 20-year historical series of patients with pulmonary hamartoma undergoing surgical resection, aiming to evaluate the characteristics, the outcomes, and the association between hamartoma and lung cancer. Methods It was a retrospective multicenter study including the data of all consecutive patients with pulmonary hamartoma undergoing surgical resection. The end-points were to evaluate: (i) the characteristics of hamartoma, (ii) outcomes, and (iii) whether hamartoma was a predictive factor for lung cancer development Results Our study population included 540 patients. Upfront surgical or endoscopic resection was performed in 385 (71%) cases while in the remaining 155 (29%) cases, the lesions were resected 20 ± 3.5 months later due to increase in size. In most cases, lung sparing resection was carried out including enucleation ( n  = 259; 48%) and wedge resection ( n  = 230; 43%) while 5 (1%) patients underwent endoscopic resection. Only two patients (0, 2%) had major complications. One patient (0.23%) had recurrence after endoscopic resection, while no cases of malignant degeneration were seen (mean follow-up:103.3 ± 93 months). Seventy-six patients (14%) had associated lung cancer, synchronous in 9 (12%) and metachronous in 67 (88%). Only age > 70-year-old ( p  = 0.0059) and smokers > 20 cigarettes/day ( p  < 0.0001) were the significant risk factors for lung cancer. Conclusion PH was a benign tumor, with no evidence of recurrence and/or of malignant degeneration after resection. The association between hamartoma and lung cancer was a spurious phenomenon due to common risk factors.

Cytomegalovirus (CMV) reactivations are strong stimulators of immune-reconstitution (IR) in hematopoietic stem cell transplantation (HSCT) recipients. Herein, we analyzed 317 CMV-seropositive consecutive patients (n = 109 letermovir, LTV; n = 208 no-LTV), undergoing HSCT with post-transplant cyclophosphamide (PTCy) and calcineurin inhibitor- (CNI) free graft-versus-host-disease (GvHD) prophylaxis. At day+90, median CD19+/mm3 was higher in LTV-cohort: 5.5 [0;439] versus 2 [0;294], p = 0.008; median CD3+/mm3 counts were lower in LTV-cohort, with no differences in CD4+, CD8+ and NK-cells. At day+180 median CD3+, CD4+ and CD8+/mm3 values were comparable between groups. Higher CD19+/mm3 counts were observed in LTV-cohort: 62 [0; 2983] versus 42 [0; 863]. Significantly higher median NK/mm3 values were seen in LTV-cohort: 225.5 [0;763] versus 163.5 [0;1181], p = 0.0003. The impact of LTV on B-cell IR at 3 months and NK-cell levels at 6 months was retained in multivariate analysis (p < 0.01), whereas the effect on T-cells was not confirmed. Moreover, we confirmed a significant reduction of clinically-relevant CMV, and moderate-to- severe chronic GvHD in LTV-cohort. Overall, in our study the use of LTV was associated with a slight improvement of B-cell and NK-cells reconstitution, with only minor impact on T-cell subsets, giving new insights on polyclonal IR for HSCT recipients in the LTV era.