661 research outputs found

    Go to the city: Urban invasions of four pipistrelle bat species in eastern Slovakia

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    Until now, late summer or autumn invasions into inhabited building have been regarded as phenomenon typical for the common pipistrelle, pipistrellus pipistrellus, exclusively. During the investigation of this phenomenon in the city of Košice (eastern Slovakia), we discovered that it was not always entirely specific for this species. During the period 2016–2018, we recorded 3 events out of 35 invasions, where small groups of common pipistrelles that invaded into inhabited buildings were also accompanied by individuals of two con-generic bat species, pipistrellus pygmaeus and pipistrellus kuhlii. Cryptic species p. pipistrellus and p. pygmaeus were determined by genetic test. In addition, in 2019, we recorded the first winter occurrence of another pipistrelle species, pipistrellus nathusii, inthis urban environment. We conclude that areas of frequent invasive behaviour of p. pipistrellus may be sometimes associated with concomitant occurrence of other related species that share common thermal or foraging niche and such behaviour could be evidence of their urbanisation tendencies

    Digestive enzymes in Rhinolophus euryale (Rhinolophidae, Chiroptera) are active also during hibernation

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    During the winter, bats use hibernation as a means of surviving the period of low prey offer. However, the Mediterranean horseshoe bat (Rhinolophus euryale) arouses from torpor quite frequently. Based on the actual climatic conditions, it can profit from occasional foraging oportunities, when they occur. We analysed faeces collected on four nights during the period from November 2012 to February 2013 from the Domica-Baradla cave system (Slovakia and Hungary). In mid-November, the largest proportion of faecal contents were from Lepidoptera. Later on, the proportion of non-consumptive mass in the faeces increased and prey remnants disappeared. We analysed the activity of digestive enzymes (amylase, chitobiase, endochitinase and glukosaminidase) in faeces. The activity of these enzymes was detected in fresh faeces throughout the whole winter. The faecal activity of the chitinases was relatively stable during the monitored period, whilst the activity of amylase was highest during late November and December. Some level of active digestive enzymes during the winter could be an adaptation to occasional winter foraging

    The Status of Eelgrass, Zostera marina, as Bay Scallop Habitat: Consequences for the Fishery in the Western Atlantic

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    Zostera marina is a member of a widely distributed genus of seagrasses, all commonly called eelgrass. The reported distribution of eelgrass along the east coast of the United States is from Maine to North Carolina. Eelgrass inhabits a variety of coastal habitats, due in part to its ability to tolerate a wide range of environmental parameters. Eelgrass meadows provide habitat, nurseries, and feeding grounds for a number of commercially and ecologically important species, including the bay scallop, Argopecten irradians. In the early 1930’s, a marine event, termed the “wasting disease,” was responsible for catastrophic declines in eelgrass beds of the coastal waters of North America and Europe, with the virtual elimination of Z. marina meadows in the Atlantic basin. Following eelgrass declines, disastrous losses were documented for bay scallop populations, evidence of the importance of eelgrass in supporting healthy scallop stocks. Today, increased turbidity arising from point and non-point source nutrient loading and sediment runoff are the primary threats to eelgrass along the Atlantic coast and, along with recruitment limitation, are likely reasons for the lack of recovery by eelgrass to pre-1930’s levels. Eelgrass is at a historical low for most of the western Atlantic with uncertain prospects for systematic improvement. However, of all the North American seagrasses, eelgrass has a growth rate and strategy that makes it especially conducive to restoration and several states maintain ongoing mapping, monitoring, and restoration programs to enhance and improve this critical resource. The lack of eelgrass recovery in some areas, coupled with increasing anthropogenic impacts to seagrasses over the last century and heavy fishing pressure on scallops which naturally have erratic annual quantities, all point to a fishery with profound challenges for survival

    A characterization of finite Chebyshev sequences in Rn

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    AbstractGiven an arbitrary totally ordered set Γ, we distinguish three types of sequences A=(ai)i∈Γ⊂Rn, called LI-, H-, and T-sequences according as det[ai1,ai2,…, ain] is non-zero for some i1<i2<…<in, is non-zero for all i1<i2<…<in, and is of constant non-zero sign for all i1<i2<…<in. In this paper we show that if Γ is of finite cardinality, then the inhomogeneous system of linear inequalities <ai, x> = αi, iϵΓ⧹B (α), sgn<ai, x> = sgnαi, iϵB (α), is solvable for all saturated α ≜ (αi)i∈Γ⊂R1 with S+(α) ⩽ n−1 iff A is a T-sequence. Here saturated means that there is a unique way of replacing the zeros of α by + 1 and – 1, in order to reach S+(α). B(α) is the union of those “intervals” of Γ of maximal cardinality ⩾ 2 (called blocks), on which α has a constant non-zero sign

    Human resources, environmental risk and implementation of lean production. The case of the first tier suppliers of the automotive industry in Spain

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    El objetivo de la presente tesis doctoral es ampliar el conocimiento sobre los factores explicativos del proceso de implantación de lean en sectores industriales investigando el papel de una serie de factores internos y externos del entorno de la empresa. En concreto, se analiza el papel de los recursos humanos, de los resultados de funcionamiento previos de la empresa y del riesgo del entorno en el proceso de implantación de lean. Ello se consigue de dos formas: 1) un revisión sistemática de la literatura sobre el papel de los recursos humanos y su gestión en el proceso de implantación y consolidación de lean y 2) a través de un estudio empírico realizado en un conjunto de proveedores de primer nivel de la industria del automóvil en España complementado con información extraida de fuentes secundarias . Los resultados alcanzados indican que existen en la literatura cuatro líneas de investigación diferenciadas sobre el papel de los recursos humanos y su gestión en el proceso de implantación de lean, mostrando lagunas y retos para la investigación futura. A nivel empírico, los resultados reafirman que Lean Production es un sistema socio-técnico integrado, donde deben gestionarse tanto factores internos como externos de la empresa para tener éxito en su proceso de implantación.The objective of this dissertation is to expand the knowledge about the explanatory factors of the implementation process of lean production in industrial sectors by investigating the role of a series of internal and external factors of the environment of the company. More specifically, this thesis analyzes the role of human resources, the past performance of the company and environmental risk in the implementation process of lean production. This is achieved in two ways: 1) a systematic literature review on the role of human resources and their management in the implementation and consolidation process of lean production, and 2) through an empirical study conducted in a set of first tier suppliers of the automobile industry in Spain complemented with information extracted from secondary data sources. The results indicate that there are four different lines of research in the literature on the role of human resources and their management in the implementation process of lean production, showing gaps and challenges for future research. At the empirical level, the results reaffirm that lean production is an integrated socio-technical system, where both internal and external factors of the company must be managed to be successful in its implementation process.Tesis Univ. Jaén. Departamento Organización de Empresas, Marketing y Sociología. Leída el 21 de abril de 2017

    Preliminary comparison of natural versus model-predicted recovery of vessel-generated seagrass injuries in Florida Keys National Marine Sanctuary

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    Each year, more than 500 motorized vessel groundings cause widespread damage to seagrasses in Florida Keys National Marine Sanctuary (FKNMS). Under Section 312 of the National Marine Sanctuaries Act (NMSA), any party responsible for the loss, injury, or destruction of any Sanctuary resource, including seagrass, is liable to the United States for response costs and resulting damages. As part of the damage assessment process, a cellular automata model is utilized to forecast seagrass recovery rates. Field validation of these forecasts was accomplished by comparing model-predicted percent recovery to that which was observed to be occurring naturally for 30 documented vessel grounding sites. Model recovery forecasts for both Thalassia testudinum and Syringodium filiforme exceeded natural recovery estimates for 93.1% and 89.5% of the sites, respectively. For Halodule wrightii, the number of over- and under-predictions by the model was similar. However, where under-estimation occurred, it was often severe, reflecting the well-known extraordinary growth potential of this opportunistic species. These preliminary findings indicate that the recovery model is consistently generous to Responsible Parties in that the model forecasts a much faster recovery than was observed to occur naturally, particularly for T. testudinum, the dominant seagrass species in the region and the species most often affected. Environmental setting (i.e., location, wave exposure) influences local seagrass landscape pattern and may also play a role in the recovery dynamics for a particular injury site. An examination of the relationship between selected environmental factors and injury recovery dynamics is currently underway. (PDF file contains 20 pages.
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