Fate of the extended states in a vanishing magnetic field: the role of spins in strongly-interacting 2D electron systems

In non-interacting or weakly-interacting 2D electron systems, the energy of the extended states increases as the perpendicular magnetic field approaches zero: the extended states "float up" in energy, giving rise to an insulator. However, in those 2D systems where metallic conductivity has been recently observed in zero magnetic field, the energy of the extended states remains constant or even decreases as B -> 0, thus allowing conduction in the limit of zero temperature. Here we show that aligning the electrons' spins causes the extended states to once more "float up" in energy in the vanishing perpendicular magnetic field, as they do for non- or weakly-interacting electrons. The difference between extended states that float up (an insulator) or remain finite (a metal) is thus tied to the existence of the spins

"Forbidden" transitions between quantum Hall and insulating phases in p-SiGe heterostructures

We show that in dilute metallic p-SiGe heterostructures, magnetic field can cause multiple quantum Hall-insulator-quantum Hall transitions. The insulating states are observed between quantum Hall states with filling factors \nu=1 and 2 and, for the first time, between \nu=2 and 3 and between \nu=4 and 6. The latter are in contradiction with the original global phase diagram for the quantum Hall effect. We suggest that the application of a (perpendicular) magnetic field induces insulating behavior in metallic p-SiGe heterostructures in the same way as in Si MOSFETs. This insulator is then in competition with, and interrupted by, integer quantum Hall states leading to the multiple re-entrant transitions. The phase diagram which accounts for these transition is similar to that previously obtained in Si MOSFETs thus confirming its universal character

“New Alien Mediterranean Biodiversity Records” (November 2021)

This Collective Article includes records of 29 alien and cryptogenic species in the Mediterranean Sea, belonging to eight Phyla (Rhodophyta, Ochrophyta, Cnidaria, Annelida, Mollusca, Arthropoda, Echinodermata, and Chordata) and coming from 11 countries. Notes published here can be divided into three different categories: occupancy estimation for wide areas, new records for the Mediterranean Sea, and new records of species expanding within the Mediterranean Sea. The first category includes a visual survey held along the coastline of Peloponnese (Greece), which yielded records of 15 species. The second category includes the first Mediterranean records of the Coho salmon Oncorhynchus kisutch (Greece) and of the Arabian monocle bream Scolopsis ghanam (Tunisia). The third category includes new records for countries (Ganonema farinosum in Malta, Cassiopea andromeda in Libya, Cingulina isseli in Greece, Okenia picoensis in Italy, Callinectes sapidus in Slovenia, Charybdis cf. hellerii in Malta, Urocaridella pulchella in Cyprus, Ablennes hians and Aluterus monoceros in Lebanon, and Fistularia petimba in Greece and Lebanon), new records for MSFD areas or regional seas (Septifer cumingii in the Greek Ionian Sea and F. petimba in the Marmara Sea), and confirmation of old, doubtful, or spurious records/statements (Branchiomma luctuosum in Tunisia, Thalamita poissonii in the Saronikos Gulf, and Pterois miles in Albania). Noteworthy, the three new records of F. petimba suggest that it may soon spread further in the Mediterranean Sea, as already happened for its congeneric Fistularia commersonii. Distributional data reported here will help tracing colonization routes of alien species in the basin and may facilitate the development of mitigation measures

Euclid preparation. XV. Forecasting cosmological constraints for the Euclid and CMB joint analysis

Galaxie

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Identification of a high frequency of chromosomal rearrangements in the centromeric regions of prostate cancer patients

The aim of the present investigation was to study the major chromosomal aberrations (CA) like deletion, translocation, inversion and mosaic in prostate cancer patients of Tamilnadu, Southern India. Totally 45 blood samples were collected from various hospitals in Tamilnadu, Southern India. Equal numbers of normal healthy subjects were chosen after signing a consent form. Volunteers provided blood samples (5 ml) to establish leukocyte cultures. Cytogenetic studies were performed by using Giemsa-banding technique and finally the results were ensured by spectral karyotyping (SKY) technique. In the present investigation, major CA like deletion, translocation, inversion and mosaic were identified in experimental subjects. Results showed frequent CA in chromosomes 1, 3, 5, 6, 7, 9, 13, 16, 18 and X. In comparison with experimental subjects, the control subjects exhibited very low levels of major CA (P<0.05). In the present study, the high frequency of centromeric rearrangements indicates a potential role for mitotic irregularities associated with the centromere in prostate cancer tumorigenesis. Identification of chromosome alterations may be helpful in understanding the molecular basis of the disease in better manner