•BPPC-IF does not necessarily admit a primitive optimal solution.•Item fragments with size equal to bin capacity cannot be simply packed into one bin.•Efficiency of the lower bound depends on the ...relative size of the maximal clique.•Proposed heuristic provides solutions with around 2
In this paper, we study the Bin Packing Problem with Conflicts and Item Fragmentation (BPPC-IF) which has applications in the delivery and storage of items that cannot be packed together. Given a set of items each with a certain size, the goal in BPPC-IF is to pack these items into a minimum number of fixed-capacity bins while not packing fragments of conflicting items into the same bin. We assume a size-preserving fragmentation, i.e., the total size of fragments of an item packed into the bins has to be equal to the item’s original size. We first prove that BPPC-IF is still NP-hard even though items can be fragmented. Unlike the Bin Packing Problem with Item Fragmentation (BPPIF), we show that BPPC-IF does not necessarily admit optimal solutions with a special structure. Moreover, we show that preprocessing an instance with oversized items (items with size greater than bin capacity) by packing a fragment of such items with size equal to bin capacity to a single bin does not necessarily yield an optimal solution. Using this observation, we develop a lower bounding procedure. Finally, we propose a heuristic algorithm which sequentially packs items into the bins using the observation about the oversized items. Through an extensive computational study, we demonstrate the superior performance of the proposed solution approach over the existing algorithms in the literature.
In vertebrates, individual Golgi stacks are joined into a compact ribbon structure; however, the relevance of a ribbon structure has been elusive. Here, we exploit the finding that the membrane ...tether of the
-Golgi network, GCC88 (encoded by
), regulates the balance between Golgi mini-stacks and the Golgi ribbon. Loss of Golgi ribbons in stable cells overexpressing GCC88 resulted in compromised mechanistic target of rapamycin (mTOR) signaling and a dramatic increase in LC3-II-positive autophagosomes, whereas RNAi-mediated depletion of GCC88 restored the Golgi ribbon and reduced autophagy. mTOR was absent from dispersed Golgi mini-stacks whereas recruitment of mTOR to lysosomes was unaffected. We show that the Golgi ribbon is a site for localization and activation of mTOR, a process dependent on the ribbon structure. We demonstrate a strict temporal sequence of fragmentation of Golgi ribbon, loss of Golgi mTOR and subsequent increased autophagy. Golgi ribbon fragmentation has been reported in various neurodegenerative diseases and we demonstrate the potential relevance of our findings in neuronal cells using a model of neurodegeneration. Overall, this study highlights a role for the Golgi ribbon in pathways central to cellular homeostasis.This article has an associated First Person interview with the first author of the paper.
To examine the factors associated with increased deoxyribonucleic acid fragmentation index (DFI), evaluate the pregnancy outcomes of men with increased DFI, and compare three independent DFI assays.
...Secondary analysis.
Nine US-based fertility centers.
Infertile men (N = 147) with sperm concentration ≤15 × 106/mL, motility ≤40%, or normal morphology ≤4% were enrolled. The female partners were ovulatory, ≤40 years old, and had documented tubal patency.
At a baseline visit, the men provided a semen sample. The couples attempted conception without assistance for 3 months and with ovarian stimulation and intrauterine insemination in the subsequent 3 months.
The DFI was analyzed using the sperm chromatin structure assay (SCSA) with increased DFI defined as >30%. The predictors of increased DFI were determined by a multivariable linear regression model. The pregnancy outcomes were compared using the χ2 test. The independent DFI assays (SCSA, deoxynucleotidyl transferase-mediated dUTP nick end labeling, and Comet) were compared with Pearson and Spearman correlations.
The 19% of men with increased DFI were older (36.0 vs. 33.0 years) and had lower total sperm motility (38.2% ± 20.5% vs. 45.2% ± 15.6%). Increased male age was found to be a significant predictor of DFI (0.75, 95% confidence interval 0.06, 1.45). Increased DFI was not associated with conception or live birth. There was a modest correlation of the deoxynucleotidyl transferase-mediated dUTP nick end labeling assay with the SCSA (r = 0.34) and Comet assay (r = 0.19).
Older age was associated with increased DFI among infertile men. The DFI assays were only weakly correlated, indicating a standard definition of DFI is needed to truly interrogate how sperm deoxyribonucleic acid fragmentation impacts male fertility.
Understanding the fate of plastics in the environment is of critical importance for the quantitative assessment of the biological impacts of plastic waste. Specially, there is a need to analyze in ...more detail the reputed longevity of plastics in the context of plastic degradation through oxidation and fragmentation reactions. Photo-oxidation of plastic debris by solar UV radiation (UVR) makes material prone to subsequent fragmentation. The fragments generated following oxidation and subsequent exposure to mechanical stresses include secondary micro- or nanoparticles, an emerging class of pollutants. The paper discusses the UV-driven photo-oxidation process, identifying relevant knowledge gaps and uncertainties. Serious gaps in knowledge exist concerning the wavelength sensitivity and the dose-response of the photo-fragmentation process. Given the heterogeneity of natural UV irradiance varying from no exposure in sediments to full UV exposure of floating, beach litter or air-borne plastics, it is argued that the rates of UV-driven degradation/fragmentation will also vary dramatically between different locations and environmental niches. Biological phenomena such as biofouling will further modulate the exposure of plastics to UV radiation, while potentially also contributing to degradation and/or fragmentation of plastics independent of solar UVR. Reductions in solar UVR in many regions, consequent to the implementation of the Montreal Protocol and its Amendments for protecting stratospheric ozone, will have consequences for global UV-driven plastic degradation in a heterogeneous manner across different geographic and environmental zones. The interacting effects of global warming, stratospheric ozone and UV radiation are projected to increase UV irradiance at the surface in localized areas, mainly because of decreased cloud cover. Given the complexity and uncertainty of future environmental conditions, this currently precludes reliable quantitative predictions of plastic persistence on a global scale.
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•Data on the fate of environmental plastic are needed to assess biological impacts.•Photo-oxidation of plastic by solar UV radiation makes it prone to fragmentation.•Implementation of the Montreal Protocol has consequences for plastic degradation.•UV-driven plastic degradation varies between locations and environments.•Knowledge gaps exist on wavelength sensitivity and dose-response of degradation.
Cerium oxide nanoparticles (CNPs) as an antioxidant have been used frequently to attenuate hyperglycaemia oxidative damage in different organs. We investigated the impact CNPs on the qualitative and ...quantitative sperm parameters, spermatogenesis and NFE2‐related factor 2 (Nrf2) expression as a major contributor of antioxidant defence in the male diabetic rats. Twenty‐four male rats were divided into four groups. Controls received only mouse food and water. Second group were treated with CNPs (30 mg kg−1 day−1) for 2 weeks. Rats in third group received streptozotocin (STZ) (60 mg/kg). In fourth group, animals became diabetic and received CNPs (30 mg kg−1 day−1) for 2 weeks. The results showed a significant abnormality in the sperm parameters and histopathological patterns of testes in the diabetic group compared to the control group and CNPs treatment significantly improved all testicular parameters. Following CNPs administration, sperm DNA fragmentation significantly reduced in the STZ‐treated rats. Moreover, after CNPs intake in the STZ‐treated rats, Nfr2 expression levels increased significantly. Overall, CNPs administration on the diabetic rates can attenuate detrimental effects of diabetes on the sperm potential fertility, sperm parameters, DNA integrity and Nrf2 expression levels. This study gives a future prospect to determine the role of CNPs in the context of diabetes.
The new wave of reform of collective forestland tenure (NRCFT) in China is considered an important policy for achieving sustainable management of forest resources. The purpose of this study is to ...investigate the influence of NRCFT on forest fragmentation in the Beijing-Tianjin-Hebei region of China based on a fixed-effects model. The forest fragmentation was analyzed based on the remote sensing images of Landsat and landscape pattern indices in the Beijing-Tianjin-Hebei region from 2000 to 2018. The results showed that (1) The NRCFT has significantly contributed to reducing forest fragmentation. (2) The effect of economic growth on forest fragmentation showed an inverted U-shape. (3) The implementation of the Grain for Green Program (GGP) and the transformation of rural energy consumption significantly reduce the degree of forest fragmentation. This study has crucial implications for formulating policies, achieving good forest governance, and reducing forest fragmentation.
Free-radical processes play an important role in functioning of living organisms. The probability of occurrence of the free-radical reactions is significantly affected by oxygen. Depending on the ...organ type and the nature of tissues and cells, the oxygen levels vary within the range of about 1 to 15%. The diffusion-limited reaction of O2 with the carbon-centered radicals of biomolecules leads to their oxidation and oxidative destruction, accompanied with formation of cytotoxic products, which is deemed to be the main cause of the damage to the lipids, nucleic acids and proteins. In our studies, we have shown that the radicals formed from hydroxyl-containing molecules under conditions of low oxygen levels undergo various fragmentation reactions before interaction with O2 takes place. These reactions result in causing damage to the initial substances and formation of bioactive products. Such reactions prevail when the reactive oxygen species interact with hydrocarbons, hydroxyl-containing glycerophospholipids, amino acids, peptides and sphingolipids.
In the report, the issues will be discussed associated with the influence of oxygen and the structure of biologically relevant substances on the probability of various free-radical transformations to occur, the possible consequences of such processes and the ways of controlling them.
•A model to consider the fragmentation effect from cased charge detonation is proposed.•It comprises non-uniform, two-zone fragmentation damage model over the element span.•Two equivalent ...cross-section heights are considered to predict the structural response.•A theoretical procedure is proposed to evaluate the cross-section height values.•The model can be employed in more realistic protective barriers design.
This paper presents methodology and calculation models that aim to enable a more realistic design of reinforced concrete (RC) protective barriers. The proposed methodology considers the global effect of fragmentation impact, which is commonly neglected in current design procedures. The analysis considers a non-uniform, two-zone damage model over the span, where the damage caused by fragment strikes is represented in the model in terms of reduced equivalent cross-section heights. It is shown that one of these zones, denoted ‘intense strip’, is significantly more damaged than the other zone. This representation of a damaged barrier, inside and outside the intense strip, should be considered for its global analysis. The proposed model was validated by comparison of its predictions with measured static load-deflection curves of plate specimens, which had been damaged by fragmentation impact in previously performed field tests. The models that are described in this paper, which provide an equivalent slab dimensions, can be used in further, more realistic dynamic analysis of the structural behavior of RC elements, subjected to combined blast and fragmentation loading.
En los cuentos Diecinueve garras y un pájaro oscuro y en la novela Cadáver exquisito, Agustina Bazterrica presenta una sociedad inquietante en la cual las relaciones humanas se han cosificado, ...automatizado; se trata de una sociedad donde unos devoran a otros; en que el consumismo y el materialismo destruyen la relación atávica entre personas, palabras y cosas que hoy están desvinculadas. A la utopía del siglo XVIII, ha seguido la atopía y hoy, la distopía, a la espera de un nuevo ordenamiento de los seres y las cosas. Agustina Bazterrica anuncia, a través de sus relatos, que es necesaria la búsqueda de nuevos códigos culturales que habiliten un mundo mejor y más solidario y una refundación del carácter de lo humano. En estos relatos elegidos puede verse un ejemplo de literatura diaspórica que muestra un mundo cotidiano cuyos personajes se valen de objetos tecnológicos y virtuales en un universo fantástico que supone la superación de la referencialidad y la verosimilitud. Estos aparatos y objetos evidencian un mundo frío, con relaciones interpersonales carentes de afecto y de sentido, en que los seres humanos canibalizados son cosas al servicio de otros que los dominan y destruyen su identidad por la fragmentación de sus cuerpos vivos o muertos.
Microplastics have adverse effects on marine life. This study examined the abundance and size of microplastics as well as their polymer types in the surface water and the bottom and beach sediments ...of Hiroshima Bay. The fragmentation process and sinking factors of foamed polystyrene (FPS) microplastics were also examined. Serious FPS pollution spread out not only in the beach sediments but also in the bottom sediments. The average size of FPS particles in the bottom sediments was significantly smaller than that of beached FPS particles. Field emission scanning electron microscopy images suggest that large amounts of microsized or nanosized FPS fragments are likely to be generated from the margins of beached FPS microplastics. X-ray computed tomography images show that FPS microplastics from the bottom sediments had tunnel-like structures inside the particle. Based on these images, FPS microplastics in the bottom sediments were susceptible to biofouling and soil deposition.
•Foamed polystyrene (FPS) could sink to the sea bottom in a coastal sea.•FPS was overwhelmingly numerically dominant in the beach and bottom sediments.•The specific surface area of smaller FPS was much greater than that of larger FPS.•FPS in the bottom sediments was susceptible to biofouling and soil deposition.
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