Subprime-asuntoluottojen arvopaperistamisen merkityksestä nykyisessä talouskriisissä

In August 2007 the credit markets ceased to function completely. Today quite a few of those who are familiar with the recent chain of events share the view that a financial technique known as securitisation was one of the prime culprits for the credit freeze, and eventually the global financial crisis. This article studies the role of securitisation of subprime mortgages in the U.S. prior to the current global financial crisis. It has been widely known for a long time to financial market participants and bystanders alike that the global banking system was transforming into a world of off-balance sheet and derivatives – the shadow banking system. At the same time, we have witnessed a dramatic change in the way we perceive the dynamics of becoming indebted. Securitisation, which primarily refers to banks’ practice of parcelling and selling loans to other investors, has been deemed one of the main tools utilised by market operators in this metamorphosis. Based on the present discussion, this article serves as an introduction to the following themes: (i) in what sense have securitised subprime mortgages been seen as the cause of the current financial crisis? This article focuses primarily on the securitisation of subprime assets prior to the financial crisis. Therefore, to enable an assessment of the presented possible explanations, it is necessary to describe (ii) the basics of the financial instruments and structures involved as well as the basics of subprime mortgage lending. In addition, as a byproduct of the two previous themes, (iii) this article will also review the reasons for the pre-crisis boom of subprime lending and securitisation. This article is primarily composed of elements from two legal disciplines, law and economics, and the law of finance. Securitisation was meant to disperse risks associated with subprime lending. The aim was to share the risks with deep-pocketed investors who were better able to absorb losses. By now it is evident that the originate-and-distribute model of selling subprime mortgages and the attendant chain of structured securities built around it has been discredited. But exactly how much of the blame should be directed towards securitisation? Securitisation is not the sole reason behind the financial crisis. Admittedly, the particular implementation of securitisation was flawed, but the technique in itself is not fundamentally wrong. With this in mind, should one go as far as to ban these recent financial innovations entirely, as has been suggested by the most critical debaters? The answer to these questions would require a further and more profound study than is possible within the scope of this article, but in the meantime one might settle for sharing Professor Bengt Holmströms’ concern that a deeper understanding of the events that led to the current financial crisis should be achieved before any major regulatory changes are made.Suomenkielinen tiivistelmä puuttuu

Prevalence and Dynamics of Pathogenic Yersinia enterocolitica 4/O:3 Among Finnish Piglets, Fattening Pigs, and Sows

Pigs are considered the main reservoir of Yersinia enterocolitica, and hence, understanding the ecology of this foodborne pathogen at the farm level is crucial. We calculated Bayesian estimates for the ability of a commercial enzyme-linked immunosorbent assay (ELISA) diagnostic test kit to detect antibodies against pathogenic Yersinia in pigs. The sensitivity and specificity of the test were 75.4% and 98.1%, respectively. We also studied the dynamics of Y. enterocolitica infection in 3 farrow-to-finish pig farms by following the same 30 pens of pigs through their lifetime from farrowing unit to slaughterhouse. Each farm was sampled 4 times, and 864 fecal and 730 serum samples were collected altogether. Pathogenic Y. enterocolitica 4/O:3 was isolated from 31.6% of the fecal samples by culturing, and Yersinia antibodies were detected in 38.2% of the serum samples with the commercial ELISA test. The pathogen was not isolated from farrowing units or all-in/all-out weaning units. However, in the weaning and fattening units using continuous management systems, the pathogen was isolated from every pen at some point of the study. After the pigs were transported into slaughterhouse, 150 tonsils were collected and 96.7% were positive by culturing. Among the strains isolated from feces and tonsils, 56 different genotypes of pathogenic Y. enterocolitica 4/O:3 were found by multilocus variable-number tandem-repeat analysis (MLVA). Finally, we collected tonsils of 266 sows from 115 farrowing farms, and Y. enterocolitica 4/O:3 was detected in 6.0% of the samples by the culture method, whereas 77.1% of the tonsils were serologically positive; the estimate for true seroprevalence was 95.8%. In conclusion, sows may not be the main source of Y. enterocolitica for piglets, although sows may still play a role in maintaining Y. enterocolitica in pig farms. Instead, pigs appear to get this foodborne pathogen mainly during the fattening period, especially if continuous management is applied.Peer reviewe

Prudent antimicrobial use is essential to prevent the emergence of antimicrobial resistance in Yersinia enterocolitica 4/O:3 strains in pigs

Yersinia enterocolitica is a psychrotrophic zoonotic foodborne pathogen. Pigs are considered the main reservoir of Y. enterocolitica 4/O:3, which is the most commonly isolated bioserotype in many European countries. Consuming pork contaminated with Y. enterocolitica can be a health threat, and antimicrobial-resistant strains may complicate the treatment of the most severe forms of yersiniosis. We analyzed the antimicrobial resistance of 1,016 pathogenic porcine Y. enterocolitica 4/O:3 strains originating from Belgium, Estonia, Finland, Germany, Italy, Latvia, Russia, Spain, and the United Kingdom. Based on available reports, we also compared antimicrobial sales for food production animals in these countries, excluding Russia. Antimicrobial resistance profiles were determined using a broth microdilution method with VetMIC plates for 13 antimicrobial agents: ampicillin, cefotaxime, ceftiofur (CTF), chloramphenicol (CHL), ciprofloxacin, florfenicol, gentamicin, kanamycin, nalidixic acid (NAL), streptomycin (STR), sulfamethoxazole (SME), tetracycline (TET), and trimethoprim (TMP). The antimicrobial resistance of Y. enterocolitica 4/O:3 strains varied widely between the countries. Strains resistant to antimicrobial agents other than ampicillin were rare in Estonia, Finland, Latvia, and Russia, with prevalence of 0.7, 0.4, 0, and 8.3%, respectively. The highest prevalence of antimicrobial resistance was found in Spanish and Italian strains, with 98 and 61% of the strains being resistant to at least two antimicrobial agents, respectively. Resistance to at least four antimicrobial agents was found in 34% of Spanish, 19% of Italian, and 7.1% of English strains. Antimicrobial resistance was more common in countries where the total sales of antimicrobials for food production animals are high and orally administered medications are common. Our results indicate that antimicrobials should be used responsibly to treat infections, and parenteral medications should be preferred to orally administered mass medications.Peer reviewe

Hand-Held Transistor Based Electrical and Multiplexed Chemical Sensing System

We describe a hand-held sensing system using a transistor based multiplexed platform and a detector that couples the electrochemical information wirelessly to a smartphone. The custom disposable platform exploits the ion-sensitive FET (ISFET) technology. Via simple surface modifications the design allows a broad range of analytes to be tested with low cost. We compared our read-out device to a commercial potentiometer using K+ as an example species analyte. The developed sensing system has a slightly better limit of detection and is notably less susceptible to external noise which is commonly observed with potentiometers. The designed platform is fabricated using standard electronic processes with gold surface and we used commercial discrete transistors as the transducing element. It can be mass produced with high yield and low cost. To circumvent the drift that typically occurs with modified solid state electrodes we incorporated a transducing layer between the electric conductor (gold pad) and the ionically conducting ion-selective membrane. The polyaniline doped with dinonylnaphtalene sulfonic acid (PANI-DNNSA) was used as a transducing layer for the first time. The PANI-DNNSA layer significantly reduces the drift of the electrodes compared to a configuration without the transducing layer. The system is easy to use with a transistor based detection that can be modified for a vast variety of existing potentiometric tests.</p

Cardiac monitoring of dogs via smartphone mechanocardiography : a feasibility study

Abstract Background In the context of monitoring dogs, usually, accelerometers have been used to measure the dog’s movement activity. Here, we study another application of the accelerometers (and gyroscopes)—seismocardiography (SCG) and gyrocardiography (GCG)—to monitor the dog’s heart. Together, 3-axis SCG and 3-axis GCG constitute of 6-axis mechanocardiography (MCG), which is inbuilt to most modern smartphones. Thus, the objective of this study is to assess the feasibility of using a smartphone-only solution to studying dog’s heart. Methods A clinical trial (CT) was conducted at the University Small Animal Hospital, University of Helsinki, Finland. 14 dogs (3 breeds) including 18 measurements (about one half of all) where the dog’s status was such that it was still and not panting were further selected for the heart rate (HR) analysis (each signal with a duration of 1 min). The measurement device in the CT was a custom Holter monitor including synchronized 6-axis MCG and ECG. In addition, 16 dogs (9 breeds, one mixed-breed) were measured at home settings by the dog owners themselves using Sony Xperia Android smartphone sensor to further validate the applicability of the method. Results The developed algorithm was able to select 10 good-quality signals from the 18 CT measurements, and for 7 of these, the automated algorithm was able to detect HR with deviation below or equal to 5 bpm (compared to ECG). Further visual analysis verified that, for approximately half of the dogs, the signal quality at home environment was sufficient for HR extraction at least in some signal locations, while the motion artifacts due to dog’s movements are the main challenges of the method. Conclusion With improved data analysis techniques for managing noisy measurements, the proposed approach could be useful in home use. The advantage of the method is that it can operate as a stand-alone application without requiring any extra equipment (such as smart collar or ECG patch)

Learning to Denoise Gated Cardiac PET Images Using Convolutional Neural Networks

Noise and motion artifacts in Positron emission tomography (PET) scans can interfere in diagnosis and result in inaccurate interpretations. PET gating techniques effectively reduce motion blurring, but at the cost of increasing noise, as only a subset of the data is used to reconstruct the image. Deep convolutional neural networks (DCNNs) could complement gating techniques by correcting such noise. However, there is little research on the specific application of DCNNs to gated datasets, which present additional challenges that are not considered in these studies yet, such as the varying level of noise depending on the gate, and performance pitfalls due to changes in the noise properties between non-gated and gated scans. To extend the current status of artificial intelligence (AI) in gated-PET imaging, we present a post-reconstruction denoising approach based on U-Net architectures on cardiac dual-gated PET images obtained from 40 patients. To this end, we first evaluate the denoising performance of four different variants of the U-Net architecture (2D, semi-3D, 3D, Hybrid) on non-gated data to better understand the advantages of each type of model, and to shed more light on the factors to take in consideration when selecting a denoising architecture. Then, we tackle the denoising of gated-PET reconstructions, revising challenges and limitations, and propose two training approaches, which overcome the need for gated targets. Quantification results show that the proposed deep learning (DL) frameworks can successfully reduce noise levels while correctly preserving the original motionless resolution of the gates.</p

Mechanocardiography-Based Measurement System Indicating Changes in Heart Failure Patients during Hospital Admission and Discharge

Heart failure (HF) is a disease related to impaired performance of the heart and is a significant cause of mortality and treatment costs in the world. During its progression, HF causes worsening (decompensation) periods which generally require hospital care. In order to reduce the suffering of the patients and the treatment cost, avoiding unnecessary hospital visits is essential, as hospitalization can be prevented by medication. We have developed a data-collection device that includes a high-quality 3-axis accelerometer and 3-axis gyroscope and a single-lead ECG. This allows gathering ECG synchronized data utilizing seismo- and gyrocardiography (SCG, GCG, jointly mechanocardiography, MCG) and comparing the signals of HF patients in acute decompensation state (hospital admission) and compensated condition (hospital discharge). In the MECHANO-HF study, we gathered data from 20 patients, who each had admission and discharge measurements. In order to avoid overfitting, we used only features developed beforehand and selected features that were not outliers. As a result, we found three important signs indicating the worsening of the disease: an increase in signal RMS (root-mean-square) strength (across SCG and GCG), an increase in the strength of the third heart sound (S3), and a decrease in signal stability around the first heart sound (S1). The best individual feature (S3) alone was able to separate the recordings, giving 85.0% accuracy and 90.9% accuracy regarding all signals and signals with sinus rhythm only, respectively. These observations pave the way to implement solutions for patient self-screening of the HF using serial measurements. </p