Hoverflies in organic apple orchards in north-western Italy

A list is given of hoverflies collected by means of Malaise and white sticky traps in two organic apple orchards in north-western Italy. The total number of collected species was 17 and it was compared with literature, in order to discuss differences due to sampling methods. The predominant species collected were Sphaerophoria scripta (L.) (73% of the total sample) and Eupeodes corollae (F.) (14%). The trend of adult captures of this species is drawn and discussed. Data on wild plant species in the orchards are also given

Energy transport between two integrable spin chains

We study the energy transport in a system of two half-infinite XXZ chains initially kept separated at different temperatures, and later connected and let free to evolve unitarily. By changing independently the parameters of the two halves, we highlight, through bosonisation and time-dependent matrix-product-state simulations, the different contributions of low-lying bosonic modes and of fermionic quasi-particles to the energy transport. In the simulations we also observe that the energy current reaches a finite value which only slowly decays to zero. The general pictures that emerges is the following. Since integrability is only locally broken in this model, a pre-equilibration behaviour may appear. In particular, when the sound velocities of the bosonic modes of the two halves match, the low-temperature energy current is almost stationary and described by a formula with a non-universal prefactor interpreted as a transmission coefficient. Thermalisation, characterized by the absence of any energy flow, occurs only on longer time-scales which are not accessible with our numerics.Comment: 15 pages, 14 figure

Robotic double-loop reconstruction method following total gastrectomy

Minimally invasive surgery for gastric cancer is a challenge. The reconstructive time is a particular issue and researchers have adopted a large variety of solutions and produced heterogeneous data. The reconstructive phase can be divided into two major categories based on the approach adopted: the execution of extracorporeal versus intracorporeal anastomosis. In turn, the surgical team can perform the latter with laparoscopic or robotic assistance. However, the question is, how should a robotic esophagojejunal anastomosis be performed after total gastrectomy? Most articles in the literature have reported the execution of mechanical anastomoses [1] [2] [3] [4] [5] [6], especially with circular staplers via the creation of a manual purse-string around the anvil. Other solutions have described the use of the Orvil or the overlap technique. Only three authors have reported intracorporeal sutures with a completely robotic-sewn anastomosis [7] [8] [9]. A new robotic technique (the Parisi technique) was developed and adopted at St. Mary’s Hospital, Terni, Italy. A double-loop reconstruction method with an intracorporeal robot-sewn anastomosis is performe

Heat treatment of aluminium alloys produced by laser powder bed fusion: A review

Abstract Laser powder bed fusion (LPBF) is the most widely used additive manufacturing technique and has received increasing attention owing to the high design freedom it offers. The production of aluminium alloys by LPBF has attracted considerable interest in several fields due to the low density of the produced alloys. The peculiar solidification conditions experienced by molten metal during the SLM process and its layer-by-layer nature causes a variety of microstructural peculiarities including the formation of metastable phases and supersaturated solid solutions, extreme microstructural refinement, and generation of residual stresses. Therefore, post-build heat treatments, which are commonly applied to conventionally produced aluminium alloys, may need to be modified in order to be adapted to the peculiar metallurgy of aluminium alloys manufactured using LPBF and address the specific issues resulting from the process itself. A number of studies have investigated this topic in recent years, proposing different approaches and dealing with various alloying systems. This paper reviews scientific research results in the field of heat treatment of selective laser melted aluminium alloys; it aims at providing a comprehensive understanding of the relationship between the induced microstructure and the resulting mechanical behaviour, as a function of the various treatment strategies

Selective laser melting of high-strength primary AlSi9Cu3 alloy: Processability, microstructure, and mechanical properties

Abstract The present work explores the possibility of employing the selective laser melting technique to produce parts in AlSi9Cu3 alloy. This alloy, currently prepared by high-pressure dye casting and intended for automotive application, may benefit from the refined microstructure commonly induced by additive manufacturing techniques. The process parameters were systematically varied to achieve full density, and the resulting defects were studied. Thereafter, microstructural features were analyzed, revealing that the high cooling rate, induced by the process, caused a large supersaturation of the aluminum matrix and the refinement of the eutectic structure. Again, the precipitation of the reinforcing θ phase provided numerous nucleation sites. These features were found to be related to the mechanical behavior of the SLMed AlSi9Cu3 alloy, which outperformed the conventional casted alloy in terms of elongation to failure and strain hardening rate both in the as-built and heat treated conditions

The influence of rock mass fracturing on splitting and contour blasts

Splitting and contour blasting are aimed to achieve suitable profiles by cutting along a surface, while common blasting is intended to detach and to fragment relevant rock volumes by increasing the fracturing state. These techniques are adopted in both underground works (tunnels, caverns, quarries) and also for surface excavations (quarries, mines, rock slopes engineering). Contour blasts are widely used techniques in mining and civil engineering to enhance performance while maintaining the safety of personnel and infrastructure. Splitting blasts are mainly used in dimension stone mining to obtain intact blocks of valuable ornamental stone. The parameters of controlled blasting (geometry, charge, blast agent) require an accurate selection using optimised blasting patterns and explosive properties; most of the proposed methods are limited and unsatisfactory due to insufficient consideration of rock mass properties. A quick but effective comparison and analysis of the different characteristics of the rock mass and its heterogeneities is presented, as it indicates a better strategy to determine a tailored blasting design for a given site, thus significantly improving the contour blasting quality

Star-finite coverings of Banach spaces

We study star-finite coverings of infinite-dimensional normed spaces. A family of sets is called star-finite if each of its members intersects only finitely many other members of the family. It follows by our results that an LUR or a uniformly Fr\'echet smooth infinite-dimensional Banach space does not admit star-finite coverings by closed balls. On the other hand, we present a quite involved construction proving existence of a star-finite covering of $c_0(\Gamma)$ by Fr\'echet smooth centrally symmetric bounded convex bodies. A similar but simpler construction shows that every normed space of countable dimension (and hence incomplete) has a star-finite covering by closed balls

Laparoscopic peritoneal lavage. Our experience and review of the literature

NTRODUCTION: Over the years various therapeutic techniques for diverticulitis have been developed. Laparoscopic peritoneal lavage (LPL) appears to be a safe and useful treatment, and it could be an effective alternative to colonic resection in emergency surgery. AIM: This prospective observational study aims to assess the safety and benefits of laparoscopic peritoneal lavage in perforated sigmoid diverticulitis. MATERIAL AND METHODS: We surgically treated 70 patients urgently for complicated sigmoid diverticulitis. Thirty-two (45.7%) patients underwent resection of the sigmoid colon and creation of a colostomy (Hartmann technique); 21 (30%) patients underwent peritoneal laparoscopic lavage; 4 (5.7%) patients underwent colostomy by the Mikulicz technique; and the remaining 13 (18.6%) patients underwent resection of the sigmoid colon and creation of a colorectal anastomosis with a protective ileostomy. RESULTS: The 66 patients examined were divided into 3 groups: 32 patients were treated with urgent surgery according to the Hartmann procedure; 13 patients were treated with resection and colorectal anastomosis; 21 patients were treated urgently with laparoscopic peritoneal lavage. We had no intraoperative complications. The overall mortality was 4.3% (3 patients). In the LPL group the morbidity rate was 33.3%. CONCLUSIONS: Currently it cannot be said that LPL is better in terms of mortality and morbidity than colonic resection. These data may, however, be proven wrong by greater attention in the selection of patients to undergo laparoscopic peritoneal lavage