Inferring comparative advantage via entropy maximization

We revise the procedure proposed by Balassa to infer comparative advantage, which is a standard tool, in Economics, to analyze specialization (of countries, regions, etc.). Balassa's approach compares the export of a product for each country with what would be expected from a benchmark based on the total volumes of countries and products flows. Based on results in the literature, we show that the implementation of Balassa's idea generates a bias: the prescription of the maximum likelihood used to calculate the parameters of the benchmark model conflicts with the model's definition. Moreover, Balassa's approach does not implement any statistical validation. Hence, we propose an alternative procedure to overcome such a limitation, based upon the framework of entropy maximisation and implementing a proper test of hypothesis: the `key products' of a country are, now, the ones whose production is significantly larger than expected, under a null-model constraining the same amount of information employed by Balassa's approach. What we found is that countries diversification is always observed, regardless of the strictness of the validation procedure. Besides, the ranking of countries' fitness is only partially affected by the details of the validation scheme employed for the analysis while large differences are found to affect the rankings of products Complexities. The routine for implementing the entropy-based filtering procedures employed here is freely available through the official Python Package Index PyPI

Comparison of 5-year progression of retinitis pigmentosa involving the posterior pole among siblings by means of SD-OCT: a retrospective study

The blockchain technology promises to transform finance, money and evengovernments. However, analyses of blockchain applicability and robustness typicallyfocus on isolated systems whose actors contribute mainly by running the consensusalgorithm. Here, we highlight the importance of considering trustless platformswithin the broader ecosystem that includes social and communication networks. Asan example, we analyse the flash-crash observed on 21st June 2017 in the Ethereumplatform and show that a major phenomenon of social coordination led to acatastrophic cascade of events across several interconnected systems. We proposethe concept of “emergent centralisation” to describe situations where a single systembecomes critically important for the functioning of the whole ecosystem, and arguethat such situations are likely to become more and more frequent in interconnectedsocio-technical systems. We anticipate that the systemic approach we propose willhave implications for future assessments of trustless systems and call for the attentionof policy-makers on the fragility of our interconnected and rapidly changing world

The effects of hypoxia on zooplankton population estimates and migration in lakes

Many zooplankton species typically exhibit diel vertical migration (DVM), where zooplankton migrate from the hypolimnion to the epilimnion of lakes at night. Zooplankton exhibit this behavior to avoid visual predators and UV radiation by remaining in the bottom waters during the day and ascending to the surface waters to feed on phytoplankton at night. However, hypoxic conditions in the hypolimnion of lakes mayinterfere with DVM and force zooplankton to increase diel horizontal migration (DHM) to find predation refuge in littoral zones. Climate change and eutrophication are expected to increase the prevalence and severity of hypoxic conditions worldwide and thereby possibly alter zooplankton migration patterns. We hypothesize that hypoxia will force zooplankton to shift their migration patterns from predominantly DVM to DHM to avoid oxygen-depleted bottom waters. To test our hypothesis, we are conducting a standardized global sampling program to test whether pelagic, full water column estimates of zooplankton are greater at night versus the day under hypolimnetic hypoxic versus oxic conditions. Participants are aiming to sample at least one lake with an oxic hypolimnion and one lake with a hypoxic hypolimnion during the thermally-stratified period at midday and midnight. With our global dataset (currently expecting about 60 lakes in 22 countries), our goal is to improve our understanding of how global change may alter zooplankton migration behavior and patterns in lakes.info:eu-repo/semantics/publishedVersio

Inferring comparative advantage via entropy maximization

We revise the procedure proposed by Balassa to infer comparative advantage, which is a standard tool in Economics to analyze specialization (of countries, regions, etc). Balassa’s approach compares a country’s export of a given product with what would be expected from a benchmark based on the total volumes of countries and product flows. Based on results in the literature, we show that implementing Balassa’s idea leads to conditions for estimating parameters conflicting with the information content of the model itself. Moreover, Balassa’s approach does not implement any statistical validation. Hence, we propose an alternative procedure to overcome such a limitation, based upon the framework of entropy maximization and implementing a proper test of hypothesis: the ‘key products’ of a country are, now, the ones whose production is significantly larger than expected, under a null-model constraining the same amount of information defining Balassa’s approach. What we found is that country diversification is always observed, regardless of the strictness of the validation procedure. Besides, the ranking of countries’ fitnesses is only partially affected by the details of the validation scheme employed for the analysis while large differences are found to affect the rankings of product complexities. The routine for implementing the entropy-based filtering procedures employed here is freely available through the official Python Package Index PyPI

Myocardial Protection in Heart Transplantation Using Blood Cardioplegia: 12 Years Outcome of a Prospective Randomized Trial

BACKGROUND: Blood cardioplegia yields a lower prevalence of right heart failure, arrhythmias, and myocardial ischemia early after heart transplantation (HTx). Because depolarizing (high [K(+)]) cardioplegic solutions may alledgedly cause endothelial damage, the 12-year outcome of a prospective randomized trial was reviewed. METHODS: Between January 1997 and March 1998, 47 consecutive patients received crystalloid (Group 1, n = 27) or blood cardioplegia (Group 2, n = 20). The groups were similarly matched: recipient age (54 ± 11 vs 55 ± 7 years, p = 0.9), sex (89% vs 90% males, p = 0.9), diagnosis (63% vs 65% dilated cardiomyopathy, p = 0.8), elevated (>4 WU) pulmonary vascular resistance (30% vs 30%, p = 0.9), prior operations (22% vs 30%, p = 0.5), urgent HTx (7% vs 20%, p = 0.2), donor age (32 ± 11 vs 31 ± 13 years, p = 0.7), donor sex (78% vs 70% males, p = 0.5), donor cause of death (33% vs 40% vascular, p = 0.5), and global myocardial ischemia (176 ± 51 vs 180 ± 58 minutes p = 0.5). Hemodynamically unstable donors were more prevalent in Group 2 (15% vs 45%, p = 0.02). The 45 hospital survivors underwent yearly echocardiography, coronary angiography, and coronary intravascular ultrasound (IVUS) imaging during follow-up. RESULTS: During follow-up (10.4 ± 5.2, range, 0.9-12.7 years), Groups 1 and 2 had comparable mortality (46% vs 42%, p = 0.7) and cause of death (chronic rejection: 50% vs 50%; neoplasia: 33% vs 25%, p = 0.8). Survival at 12 years was 50% ± 12% vs 52% ± 11% (p = 0.9). Follow-up echocardiogram showed similar mean left ventricular ejection fraction (LVEF; 47% ± 12% vs 49% ± 11%, p = 0.7) and prevalence of LVEF 0.5 mm) in the proximal and distal left anterior descending artery (67% vs 40%; 58% vs 45%) and higher number of percutaneous coronary interventions (2.7 ± 0.5 vs 1.8 ± 0.3, p = 0.3) was noted in Group 1. CONCLUSIONS: Use of blood cardioplegia is safe and results in comparable survival and prevalence of adverse events late after HTx. The trend towards greater freedom from chronic rejection and more limited extent of coronary artery disease in grafts protected with blood cardioplegia awaits confirmation

Surgical treatment of postinfarction left ventricular free wall rupture

Background: Left ventricular free wall rupture (LVFWR) is still one of the often fatal complications of acute myocardial infarction. Surgical repair is mandatory even with high operative mortality. The optimal surgical technique is controversial since the results depend on type of rupture. We present our mid-term surgical experience according to the status of the left ventricular tear and type of surgical repair.Methods: From January 1997 to December 2007, 19 consecutive patients with LVFWR were treated at our institution. The mean age was 72 ± 8 ranging from 53 to 81 years; there were eight males and 11 females. According to the intraoperative findings, patients were divided into two groups: group 1 (eight patients), where no macroscopic tear of the LVFW could be detected with blood oozing from infarcted zone (Oozing type LVFWR); and group 2 (11 patients), where a macroscopic defect of the epicardium, with free communication between left ventricular cavity and pericardial space, was identified (Blow-out type LVFWR). The patch covering and glue technique was applied for group 1 patients, while closure of the ventricular tear either by direct suture or by patch repair was used for group 2 patients. Results: The interval between diagnosis of LVFWR and surgery was 2.9 ± 1.1 hours. However, reevaluation of echocardiographic studies showed an early missed diagnosis of LVFWR in three patients of group 1 and in eight of group 2. Thus,the mean interval between initial signs of rupture and surgery was 9 ± 8 hours and 21 ± 15 hours, respectively, for oozing and blow-out type rupture. On arrival in the operating room, four patients were oncardiopulmonary resuscitation, while four were in cardiogenic shock. The hospital mortality was 12% (one death) in group 1 and 36% (four deaths) in group 2 mainly due to multiorgan failure. Fourteen patients were discharged with a mean follow-up of 3.8 ± 3.5 years. During follow-up, one patient in group 1 died after 7.5 years. No recurrence of free wall rupture or aneurysm formation was demonstrated in all cases. At last follow-up, all survivors showed excellent clinical results with a preserved left ventricular function. Patients with oozing type LVFWR and patch covering technique repair showed an absence of left ventricularrestricted motion at the echocardiographic study. Conclusion: In patients with LVFWR, early diagnosis and surgical treatment are crucial for successful outcome when excellent results can be achieved with a simple glued patch covering techniqu

Space applications of Si/BProceedings of SPIE

In the extreme ultra-violet region, multilayer coatings are the only technique to obtain high reflectivity in normal incidence optical configurations. The interference process which regulates periodic multilayers behavior offers narrow-band spectral filtering without the use of additional filters, fact that makes these coatings particularly suitable for lines emission observations. Despite the large amount of possible materials combinations, Mo/Si multilayers are the standard choice for space research on plasma physics in the 13 - 30 nm spectral region. In this work Si/B4C is presented as an alternative material couple for the 30.4 nm selection. Attractive features are the better spectral purity and the second order reflectivity reduction. A possible application to the Sounding CORonagraph Experiment is described as an example. B4C thin films have been used to characterize this material in terms of optical constants in the 40 nm - 150 nm spectral region where, currently, only few data are available

Space application of Si/B4C multilayer coating at extreme ultra-violet region; comparison with standard Mo/Si coatings

In the extreme ultra-violet region, multilayer coatings are the only technique to obtain high reflectivity in normal incidence optical configurations. The interference process which regulates periodic multilayers behavior offers narrow-band spectral filtering without the use of additional filters, fact that makes these coatings particularly suitable for lines emission observations. Despite the large amount of possible materials combinations, Mo/Si multilayers are the standard choice for space research on plasma physics in the 13 - 30 nm spectral region. In this work Si/B4C is presented as an alternative material couple for the 30.4 nm selection. Attractive features are the better spectral purity and the second order reflectivity reduction. A possible application to the Sounding CORonagraph Experiment is described as an example. B4C thin films have been used to characterize this material in terms of optical constants in the 40 nm - 150 nm spectral region where, currently, only few data are available