نتایج جستجو برای: and zig bee

تعداد نتایج: 16830997  

Journal: :Annals of the New York Academy of Sciences 2010
Rachael Winfree

Bees pollinate most of the world's wild plant species and provide economically valuable pollination services to crops; yet knowledge of bee conservation biology lags far behind other taxa such as vertebrates and plants. There are few long-term data on bee populations, which makes their conservation status difficult to assess. The best-studied groups are the genus Bombus (the bumble bees), and b...

2015
Olivia M. Bernauer Hannah R. Gaines-Day Shawn A. Steffan Brian T. Forschler

Bees provide vital pollination services to the majority of flowering plants in both natural and agricultural systems. Unfortunately, both native and managed bee populations are experiencing declines, threatening the persistence of these plants and crops. Agricultural chemicals are one possible culprit contributing to bee declines. Even fungicides, generally considered safe for bees, have been s...

Journal: :Ecological applications : a publication of the Ecological Society of America 2010
Ralph Grundel Robert P Jean Krystalynn J Frohnapple Gary A Glowacki Peter E Scott Noel B Pavlovic

Given bees' central effect on vegetation communities, it is important to understand how and why bee distributions vary across ecological gradients. We examined how plant community composition, plant diversity, nesting suitability, canopy cover, land use, and fire history affected bee distribution across an open-forest gradient in northwest Indiana, USA, a gradient similar to the historic Midwes...

2016
Gihyun Lee Hyunsu Bae

Bee venom therapy has been used to treat immune-related diseases such as arthritis for a long time. Recently, it has revealed that group III secretory phospholipase A2 from bee venom (bee venom group III sPLA2) has in vitro and in vivo immunomodulatory effects. A growing number of reports have demonstrated the therapeutic effects of bee venom group III sPLA2. Notably, new experimental data have...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
Jeroen Scheper Menno Reemer Ruud van Kats Wim A Ozinga Giel T J van der Linden Joop H J Schaminée Henk Siepel David Kleijn

Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for s...

This paper presents a static analysis of laminated composite doubly-curved shells using refined kinematic models with polynomial and non-polynomial functions recently introduced in the literature. To be specific, Maclaurin, trigonometric, exponential and zig-zag functions are employed. The employed refined models are based on the equivalent single layer theories. A simply supported shell is sub...

Journal: :journal of optimization in industrial engineering 2011
mohamad mirzazadeh gholam hasan shirdel behrooz masoumi

assigning facilities to locations is one of the important problems, which significantly is influence in transportation cost reduction. in this study, we solve quadratic assignment problem (qap), using a meta-heuristic algorithm with deterministic tasks and equality in facilities and location number. it should be noted that any facility must be assign to only one location. in this paper, first o...

Journal: :Discrete Applied Mathematics 2007
Haizhen Ren Fuji Zhang

Double hexagonal chains” can be considered as benzenoids constructed by successive fusions of successive naphthalenes along a zig-zag sequence of triples of edges as appear on opposite sides of each naphthalene unit. In this paper, we discuss the numbers of k-matchings and k-independent sets of double hexagonal chains, as well as Hosoya indices and Merrifield–Simmons indices, and obtain some ex...

2015
Kamalpreet Kaur Shiv Kumar Verma

Digital watermarking is an important technology in today’s world for protecting multimedia content from illegal copying of data. It is a process of concealing information. The main purpose of digital watermarking provided more robustness and integrity against geometrical attacks. In this paper, various digital watermarking techniques have been discussed and identified the best technique by comp...

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